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COMPOUND SUMMARY Tryptophan

PubChem CID 6305

Structure

2D 3D Crystal

Find Similar Structures

Chemical Safety Laboratory Chemical Safety Summary (LCSS) Datasheet

Molecular Formula C11H12N2O2 L-tryptophan 73-22-3 tryptophan Synonyms L-Tryptophane (S)-Tryptophan

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Molecular Weight 204.22 g/mol

Modify Create Dates 2021-01-02 2004-09-16

Tryptophan is the least plentiful of all 22 amino acids and an essential amino acid in humans (provided by food), Tryptophan is found in most proteins and a precursor of serotonin. Tryptophan is converted to 5-hydroxy-tryptophan (5-HTP), converted in turn to serotonin, a neurotransmitter essential in regulating appetite, sleep, mood, and pain. Tryptophan is a natural sedative and present in dairy products, meats, brown rice, fish, and soybeans. (NCI04)

NCI Thesaurus (NCIt)

Source: NCI Thesaurus (NCIt) Record Name: Tryptophan URL: https://ncit.nci.nih.gov/ncitbrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&ns=NCI_Thesaurus&code=C29603 Description: NCI Thesaurus (NCIt) provides reference terminology for many systems. It covers vocabulary for clinical care, translational and basic research, and public information and administrative activities. License Note: Unless otherwise indicated, all text within NCI products is free of copyright and may be reused without our permission. Credit the National Cancer Institute as the source. License URL: https://www.cancer.gov/policies/copyright-reuse

L-tryptophan is the L-enantiomer of tryptophan. It has a role as an antidepressant, a nutraceutical, a micronutrient, a plant metabolite, a human metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite and a mouse metabolite. It is an erythrose 4-phosphate/phosphoenolpyruvate family amino acid, a proteinogenic amino acid, a tryptophan and a L-alpha-amino acid. It is a conjugate base of a L-tryptophanium. It is a conjugate acid of a L-tryptophanate. It is an enantiomer of a D-tryptophan. It is a tautomer of a L-tryptophan zwitterion.

ChEBI

Source: ChEBI Record Name: L-tryptophan URL: http://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:16828 Description: Chemical Entities of Biological Interest (ChEBI) is a database and ontology of molecular entities focused on 'small' chemical compounds, that is part of the Open Biomedical Ontologies effort. The term "molecular entity" refers to any constitutionally or isotopically distinct atom, molecule, ion, ion pair, radical, radical ion, complex, conformer, etc., identifiable as a separately distinguishable entity.

L-tryptophan is a white powder with a flat taste. An essential amino acid; occurs in isomeric forms. (NTP, 1992)

CAMEO Chemicals

Source: CAMEO Chemicals Record Name: L-TRYPTOPHAN URL: https://cameochemicals.noaa.gov/chemical/21204 Description: CAMEO Chemicals is a chemical database designed for people who are involved in hazardous material incident response and planning. CAMEO Chemicals contains a library with thousands of datasheets containing response-related information and recommendations for hazardous materials that are commonly transported, used, or stored in the United States. CAMEO Chemicals was developed by the National Oceanic and Atmospheric Administration's Office of Response and Restoration in partnership with the Environmental Protection Agency's Office of Emergency Management. License Note: CAMEO Chemicals and all other CAMEO products are available at no charge to those organizations and individuals (recipients) responsible for the safe handling of chemicals. However, some of the chemical data itself is subject to the copyright restrictions of the companies or organizations that provided the data. License URL: https://cameochemicals.noaa.gov/help/reference/terms_and_conditions.htm?d_f=false

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 1/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

1 Structures

1.1 2D Structure

Chemical Structure Depiction

PubChem

1.2 3D Conformer

Interactive Chemical Structure Model

Ball and Stick

Sticks

Wire-Frame

Space-Filling

Show Hydrogens

Animate

PubChem

1.3 Crystal Structures

Showing 1 of 3 View More

CCDC Number 986568

Crystal Structure Data DOI:10.5517/cc123lsk

Crystal Structure Depiction

Associated Article DOI:10.1107/S0108768112033484

The Cambridge Structural Database

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 2/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

2 Biologic Description

SVG Image

IUPAC Condensed H-Trp-OH

Sequence W

PLN H-W-OH

HELM PEPTIDE1{W}$$$$

IUPAC L-tryptophan

PubChem

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 3/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

3 Names and Identifiers

3.1 Computed Descriptors

3.1.1 IUPAC Name

(2S)-2-amino-3-(1H-indol-3-yl)propanoic acid Computed by LexiChem 2.6.6 (PubChem release 2019.06.18)

PubChem

3.1.2 InChI

InChI=1S/C11H12N2O2/c12-9(11(14)15)5-7-6-13-10-4-2-1-3-8(7)10/h1-4,6,9,13H,5,12H2,(H,14,15)/t9-/m0/s1 Computed by InChI 1.0.5 (PubChem release 2019.06.18)

PubChem

3.1.3 InChI Key

QIVBCDIJIAJPQS-VIFPVBQESA-N Computed by InChI 1.0.5 (PubChem release 2019.06.18)

PubChem

3.1.4 Canonical SMILES

C1=CC=C2C(=C1)C(=CN2)CC(C(=O)O)N Computed by OEChem 2.1.5 (PubChem release 2019.06.18)

PubChem

3.1.5 Isomeric SMILES

C1=CC=C2C(=C1)C(=CN2)C[C@@H](C(=O)O)N Computed by OEChem 2.1.5 (PubChem release 2019.06.18)

PubChem

3.2 Molecular Formula

C11H12N2O2

CAMEO Chemicals; Wikipedia; PubChem

3.3 Other Identifiers

3.3.1 CAS

73-22-3

ChemIDplus; DrugBank; DTP/NCI; EPA Chemicals under the TSCA; EPA DSSTox; European Chemicals Agency (ECHA); Hazardous Substances Data Bank (HSDB); Human Metabolome Database (HMDB)

3.3.2 Deprecated CAS

6912-86-3, 80206-30-0, 154635-35-5

ChemIDplus

3.3.3 European Community (EC) Number

200-795-6

European Chemicals Agency (ECHA)

3.3.4 NSC Number

757373

DTP/NCI

3.3.5 UNII https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 4/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

8DUH1N11BX

FDA/SPL Indexing Data

3.3.6 DSSTox Substance ID

DTXSID5021419

EPA DSSTox

3.3.7 Wikipedia

Tryptophan

Wikipedia

3.4 Synonyms

3.4.1 MeSH Entry Terms

Ardeydorm ratio-Tryptophan Ardeytropin Trofan L Tryptophan Tryptacin L Tryptophan ratiopharm Tryptan L-Tryptophan Tryptophan L-Tryptophan-ratiopharm Tryptophan Metabolism Alterations Levotryptophan Lyphan Naturruhe Optimax PMS Tryptophan PMS-Tryptophan ratio Tryptophan

MeSH

3.4.2 Depositor-Supplied Synonyms

L-tryptophan (2S)-2-amino-3-(1H-indol-3-yl)propanoic acid Tryptophan (VAN) Tryptophan, L- trp 73-22-3 Pacitron 1-beta-3-Indolylalanine Alanine, 3-indol-3-yl- (L)-TRYPTOPHAN tryptophan Indole-3-alanine Tryptophan (H-3) (S)-2-Amino-3-(3-indolyl)propionic acid (-)-Tryptophan L-Tryptophane Kalma Triptofano [Spanish] alpha'-Amino-3-indolepropionic acid CCRIS 617 (S)-Tryptophan L-beta-3-Indolylalanine Tryptophanum [Latin] Tryptophan [USAN:INN] L-Alanine, 3-(1H-indol-3-yl)- Tryptophane L-Tryptofan 1H-Indole-3-alanine L-alpha-amino-3-indolepropionic acid 1H-Indole-3-alanine, (S)- h-Trp-oh L-Trp 1beta-3-Indolylalanine L-alpha-Aminoindole-3-propionic acid alpha-Amino-3-indolepropionic acid, L- Optimax L-(-)-Tryptophan 2-Amino-3-indolylpropanoic acid Sedanoct HSDB 4142 trofan 3-Indol-3-ylalanine triptofano (S)-alpha-Aminoindole-3-propionic acid (S)-alpha-amino-beta-(3-indolyl)-propionic acid Tryptan Tryptophanum tryptacin 1H-Indole-3-alanine (VAN) NCI-C01729 Lyphan (S)-alpha-Amino-1H-indole-3-propanoic acid Ardeytropin EH 121 AI3-18478 Tryptophane [French]

PubChem

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 5/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

4 Chemical and Physical Properties

4.1 Computed Properties

Property Name Property Value Reference

Molecular Weight 204.22 g/mol Computed by PubChem 2.1 (PubChem release 2019.06.18)

XLogP3 -1.1 Computed by XLogP3 3.0 (PubChem release 2019.06.18)

Hydrogen Bond Donor Count 3 Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18)

Hydrogen Bond Acceptor Count 3 Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18)

Rotatable Bond Count 3 Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18)

Exact Mass 204.089878 g/mol Computed by PubChem 2.1 (PubChem release 2019.06.18)

Monoisotopic Mass 204.089878 g/mol Computed by PubChem 2.1 (PubChem release 2019.06.18)

Topological Polar Surface Area 79.1 Å² Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18)

Heavy Atom Count 15 Computed by PubChem

Formal Charge 0 Computed by PubChem

Complexity 245 Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18)

Isotope Atom Count 0 Computed by PubChem

Defined Atom Stereocenter Count 1 Computed by PubChem

Undefined Atom Stereocenter Count 0 Computed by PubChem

Defined Bond Stereocenter Count 0 Computed by PubChem

Undefined Bond Stereocenter Count 0 Computed by PubChem

Covalently-Bonded Unit Count 1 Computed by PubChem

Compound Is Canonicalized Yes Computed by PubChem (release 2019.01.04)

PubChem

4.2 Experimental Properties

4.2.1 Physical Description

L-tryptophan is a white powder with a flat taste. An essential amino acid; occurs in isomeric forms. (NTP, 1992) National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

CAMEO Chemicals

Solid

Human Metabolome Database (HMDB)

4.2.2 Color/Form

Leaflets or plates from dilute alcohol O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1682

Hazardous Substances Data Bank (HSDB)

White to slightly yellowish-white ... crystals or crystalline powder Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 61

Hazardous Substances Data Bank (HSDB)

4.2.3 Odor

Odorless Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 61

Hazardous Substances Data Bank (HSDB)

4.2.4 Taste

FLAT TASTE Sax, N.I. and R.J. Lewis, Sr. (eds.). Hawley's Condensed Chemical Dictionary. 11th ed. New York: Van Nostrand Reinhold Co., 1987., p. 1197

Hazardous Substances Data Bank (HSDB)

Slightly bitter Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 61

Hazardous Substances Data Bank (HSDB)

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554 to 558 °F (Decomposes) (NTP, 1992) National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

CAMEO Chemicals

290.5 dec °C PhysProp

DrugBank

282 °C (decomposes) Lide, D.R. CRC Handbook of Chemistry and Physics 88TH Edition 2007-2008. CRC Press, Taylor & Francis, Boca Raton, FL 2007, p. 3-514

Hazardous Substances Data Bank (HSDB)

230°C

Human Metabolome Database (HMDB)

4.2.6 Solubility

1 to 5 mg/mL at 68° F (NTP, 1992) National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

CAMEO Chemicals

13400 mg/L (at 25 °C) YALKOWSKY,SH & DANNENFELSER,RM (1992)

DrugBank

0.07 M YALKOWSKY,SH & HE,Y (2003)

EPA DSSTox

Slightly soluble in acetic acid, ethanol; insoluble in ethyl ether Lide, D.R. CRC Handbook of Chemistry and Physics 88TH Edition 2007-2008. CRC Press, Taylor & Francis, Boca Raton, FL 2007, p. 3-514

Hazardous Substances Data Bank (HSDB)

Solubility in water: 0.23 g/L at 0 °C, 11.4 g/L at 25 °C, 17.1 g/L at 50 °C, 27.95 g/L at 75 °C, 49.9 g/L at 100 °C O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1682

Hazardous Substances Data Bank (HSDB)

Soluble 1 in 100 of water; very slightly soluble in alcohol; practically insoluble chloroform and ether; soluble in hot alcohol and solutions of dilute acids and alkali hydroxides. Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 61

Hazardous Substances Data Bank (HSDB)

13.4 mg/mL at 25 °C YALKOWSKY,SH & DANNENFELSER,RM (1992)

Human Metabolome Database (HMDB)

4.2.7 Vapor Pressure

2.1X10-9 mm Hg at 25 °C (est) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.0. Jan, 2009. Available from, as of Aug 13, 2010: http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm

Hazardous Substances Data Bank (HSDB)

4.2.8 LogP

-1.06 HANSCH,C ET AL. (1995)

DrugBank

-1.05 (LogP) HANSCH,C ET AL. (1995)

EPA DSSTox

log Kow = -1.06 Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 84 https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 7/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Hazardous Substances Data Bank (HSDB)

-1.06 HANSCH,C ET AL. (1995)

Human Metabolome Database (HMDB)

4.2.9 LogS

-1.23 ADME Research, USCD

DrugBank

4.2.10 Optical Rotation

Specific optical rotation: -31.5 deg at 23 °C/D (water, 1%), +2.4 deg at 20 °C/D (hydrochloric acid, 0.5 N); +0.15 deg at 20 °C/D (sodium hydroxide, 2.43% in 0.5 N) O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1682

Hazardous Substances Data Bank (HSDB)

Specific optical rotation: +6.1 deg at 20 °C/D (In Sodium hydroxide, 11%) Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V5: 5159

Hazardous Substances Data Bank (HSDB)

4.2.11 Decomposition

When heated to decomposition it emits toxic fumes of /nitric oxide/. Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 3632

Hazardous Substances Data Bank (HSDB)

4.2.12 pH

A 1% solution in water has a pH of 5.5 to 7. Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 61

Hazardous Substances Data Bank (HSDB)

4.2.13 pKa

7.38 (at 25 °C) KORTUM,G ET AL (1961)

DrugBank

4.2.14 Dissociation Constants

pK1 = 2.38 /SRC: carboxylic acid/; pK2 = 9.39 /SRC: primary amine/ O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1682

Hazardous Substances Data Bank (HSDB)

4.2.15 Collision Cross Section

154.22 Å² [M+H]+ [CCS Type: DT, Method: stepped-field] https://pubs.rsc.org/en/content/articlelanding/2017/sc/c7sc03464d

CCSbase

158.58 Å² [M-H]- [CCS Type: DT, Method: stepped-field] https://pubs.rsc.org/en/content/articlelanding/2017/sc/c7sc03464d

CCSbase

145 Å² [M+H]+ [CCS Type: TW, Method: calibrated with polyalanine] https://pubs.acs.org/doi/abs/10.1021/ac500405x

CCSbase

150.1 Å² [M+H]+ [CCS Type: DT, Method: single field calibrated with ESI Low Concentration Tuning Mix (Agilent)] https://pubs.acs.org/doi/abs/10.1021/acs.analchem.8b04322

CCSbase

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 8/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

150.3 Å² [M+H]+ [CCS Type: DT, Method: single field calibrated with ESI Low Concentration Tuning Mix (Agilent)] https://pubs.acs.org/doi/abs/10.1021/acs.analchem.8b04322

CCSbase

147.6 Å² [M+Na]+ [CCS Type: DT, Method: single field calibrated with ESI Low Concentration Tuning Mix (Agilent)] https://pubs.acs.org/doi/abs/10.1021/acs.analchem.8b04322

CCSbase

147.7 Å² [M+Na]+ [CCS Type: DT, Method: single field calibrated with ESI Low Concentration Tuning Mix (Agilent)] https://pubs.acs.org/doi/abs/10.1021/acs.analchem.8b04322

CCSbase

142.3 Å² [M-H]- [CCS Type: DT, Method: single field calibrated with ESI Low Concentration Tuning Mix (Agilent)] https://pubs.acs.org/doi/abs/10.1021/acs.analchem.8b04322

CCSbase

142.5 Å² [M-H]- [CCS Type: DT, Method: single field calibrated with ESI Low Concentration Tuning Mix (Agilent)] https://pubs.acs.org/doi/abs/10.1021/acs.analchem.8b04322

CCSbase

151.5 Å² [M-H]- [CCS Type: DT, Method: single field calibrated with ESI Low Concentration Tuning Mix (Agilent)] https://pubs.acs.org/doi/abs/10.1021/acs.analchem.8b04322

CCSbase

149.1 Å² [M-H]- 151.3 Å² [M+H]+ 147.2 Å² [M+Na]+ S50 | CCSCOMPEND | The Unified Collision Cross Section (CCS) Compendium | DOI:10.5281/zenodo.2658162

NORMAN Suspect List Exchange

4.2.16 Other Experimental Properties

Decomposes at 289 °C (rapid heating) O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1683

Hazardous Substances Data Bank (HSDB)

Needles from methanol, decomposes at 251 °C /Tryptophan hydrochloride/ O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1682

Hazardous Substances Data Bank (HSDB)

IR: 8612 (Sadtler Research Laboratories IR Grating Collection) /Tryptophan (DL)/ Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V5: 5158

Hazardous Substances Data Bank (HSDB)

UV: 3453 (Sadtler Research Laboratories Spectral Collection) /Tryptophan (DL)/ Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V5: 5158

Hazardous Substances Data Bank (HSDB)

1H NMR: 582 (Sadtler Research Laboratories Spectral Collection) /Tryptophan (DL)/ Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V5: 5158

Hazardous Substances Data Bank (HSDB)

MASS: 1229 (National Bureau of Standards EPA-NIH Mass Spectra Data Base, NSRDS-NBS-63) /Tryptophan (DL)/ Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V5: 5159

Hazardous Substances Data Bank (HSDB)

1H NMR: 582 (Sadtler Research Laboratories Spectral Collection) /Tryptophan (D)/ Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V5: 5158

Hazardous Substances Data Bank (HSDB)

MASS: 1229 (National Bureau of Standards EPA-NIH Mass Spectra Data Base, NSRDS-NBS-63) /Tryptophan (D)/ Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V5: 5158

Hazardous Substances Data Bank (HSDB)

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5 Spectral Information

5.1 1D NMR Spectra

1D NMR Spectra 1H NMR: 582 (Sadtler Research Laboratories Spectral Collection)

Hazardous Substances Data Bank (HSDB)

1D NMR Spectrum 1288 - L-Tryptophan (HMDB0000929) 1D NMR Spectra 1D NMR Spectrum 1608 - L-Tryptophan (HMDB0000929)

Human Metabolome Database (HMDB)

5.1.1 1H NMR Spectra

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Instrument Name Varian CFT-20

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SpectraBase

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SpectraBase

5.1.2 13C NMR Spectra

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Source of Sample Aldrich Chemical Company, Inc., Milwaukee, Wisconsin

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SpectraBase

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SpectraBase

5.2 2D NMR Spectra

2D NMR Spectrum 1047 - L-Tryptophan (HMDB0000929) 2D NMR Spectra 2D NMR Spectrum 1549 - L-Tryptophan (HMDB0000929)

Human Metabolome Database (HMDB)

5.3 Mass Spectrometry

Source of Spectrum J-66-4539-38

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SpectraBase

5.3.1 GC-MS

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GC-MS GC-MS Spectrum 673 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 31262 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 674 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 31263 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 675 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 676 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 1845 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 1879 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 29838 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 30108 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 30213 - L-Tryptophan (HMDB0000929) https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 11/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

GC-MS Spectrum 30316 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 30704 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 30741 - L-Tryptophan (HMDB0000929) GC-MS Spectrum 30772 - L-Tryptophan (HMDB0000929)

Human Metabolome Database (HMDB)

MoNA ID JP011293

MS Category Experimental

MS Type GC-MS

MS Level MS1

Instrument HITACHI M-2500

Instrument Type EI-B

Ionization Mode positive

Splash splash10-001i-0900000000-d054a214c1717940989f

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Submitter University of Tokyo Team, Faculty of Engineering, University of Tokyo

MassBank of North America (MoNA)

5.3.2 MS-MS

MS-MS Spectrum 1321 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4900 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 1322 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4901 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 1323 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4902 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4890 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4903 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4891 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4904 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4892 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4905 - L-Tryptophan (HMDB0000929) MS-MS MS-MS Spectrum 4893 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4906 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4894 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4907 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4895 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4908 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4896 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4909 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4897 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4910 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4898 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4911 - L-Tryptophan (HMDB0000929) MS-MS Spectrum 4899 - L-Tryptophan (HMDB0000929)

Human Metabolome Database (HMDB)

5.3.3 LC-MS

Showing 2 of 5 View More

MoNA ID MoNA010399

MS Category Experimental

MS Type LC-MS

MS Level MS1

Precursor Type [M+H]+

precursor m/z 205.097152709961

Instrument Agilent 6550 iFunnel

Instrument Type LC-ESI-QTOF

Ionization Mode Positive

Splash splash10-000i-0910000000-174e0ca9c64f45b07c88

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https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 12/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Submitter romanas chaleckis, gunma university

MassBank of North America (MoNA)

MoNA ID MoNA010400

MS Category Experimental

MS Type LC-MS

MS Level MS2

Precursor Type [M+H]+

precursor m/z 205.097152709961

Instrument Agilent 6550 iFunnel

Instrument Type LC-ESI-QTOF

Ionization Mode Positive

Splash splash10-000b-0900000000-4f1c14c6387669d15eb5

Thumbnail

Submitter romanas chaleckis, gunma university

MassBank of North America (MoNA)

5.3.4 Other MS

Showing 2 of 6 View More

Other MS MASS: 25370 (NIST/EPA/MSDC Mass Spectral Database, 1990 version); 1707 (National Bureau of Standards)

Hazardous Substances Data Bank (HSDB)

MoNA ID PR030018

MS Category Experimental

MS Type CD-MS

MS Level MS1

Instrument CE-system connected to 6210 Time-of-Flight MS, Agilent

Instrument Type CE-ESI-TOF

Ionization ESI

Ionization Mode positive

Splash splash10-0a4i-0090000000-ce0faa81be914aa3213a

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https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 13/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Submitter RIKEN Plant Science Center Team, Riken Plant Science Center

MassBank of North America (MoNA)

5.4 UV Spectra

MAX ABSORPTION (WATER): 280 NM (LOG E= 3.72) Weast, R.C. (ed.). Handbook of Chemistry and Physics. 60th ed. Boca Raton, Florida: CRC Press Inc., 1979., p. C-534

Hazardous Substances Data Bank (HSDB)

UV: 17157 (Sadtler Research Laboratories Spectral Collection) Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V5: 5159

Hazardous Substances Data Bank (HSDB)

5.5 IR Spectra

5.5.1 FTIR Spectra

Technique KBr WAFER

Source of Sample Fluka Chemie AG, Buchs, Switzerland

Thumbnail

SpectraBase

Technique Mull

Source of Spectrum Sigma-Aldrich Co. LLC.

Source of Sample Aldrich

Catalog Number T90204

Thumbnail

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 14/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

SpectraBase

5.5.2 ATR-IR Spectra

Showing 2 of 3 View More

Instrument Name Bio-Rad FTS

Technique ATR-Neat (DuraSamplIR II) ground

Source of Spectrum Forensic Spectral Research

Source of Sample Calbiochem, EMD Chemicals, Inc., an Affiliate of Merck KGaA, Darmstadt, Germany

Catalog Number 6540

Lot Number 101772

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SpectraBase

Instrument Name Bio-Rad FTS

Technique ATR-Neat (DuraSamplIR II)

Source of Spectrum Forensic Spectral Research

Source of Sample Sigma-Aldrich Company Llc

Catalog Number T0254

Lot Number 64H0331

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SpectraBase

5.6 Raman Spectra

Technique FT-Raman

Source of Spectrum Forensic Spectral Research

Source of Sample Calbiochem, EMD Chemicals, Inc., an Affiliate of Merck KGaA, Darmstadt, Germany

Catalog Number 6540

Lot Number 101772

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https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 15/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

SpectraBase

Technique FT-Raman

Source of Spectrum Forensic Spectral Research

Source of Sample Sigma-Aldrich Company LLC

Catalog Number T-0254

Lot Number 64H0331

Thumbnail

SpectraBase

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 16/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

6 Related Records

6.1 Related Compounds with Annotation

7,012 items View More Rows & Details

SORT BY Compound CID

Structure Compound CID Name Molecular Formula Molecular Weight, g/mol

144 5-Hydroxytryptophan C11H12N2O3 220.22

397 Indole-3-acetamide C10H10N2O 174.2

- 801 Indole-3-acetate C10H8NO2 174.18

802 Indole-3-acetic acid C10H9NO2 175.18

803 Indole-3-pyruvic acid C11H9NO3 203.19

1 2 3 ... 1,403 Next

PubChem

6.2 Related Compounds

Same Connectivity 82 Records

Same Stereo 49 Records

Same Isotope 3 Records

Same Parent, Connectivity 253 Records

Same Parent, Stereo 143 Records

Same Parent, Isotope 171 Records

Same Parent, Exact 92 Records

Mixtures, Components, and 340 Records Neutralized Forms

Similar Compounds 4,651 Records

Similar Conformers 3,120 Records

PubChem

6.3 Substances

6.3.1 Related Substances

All 921 Records

Same 406 Records

Mixture 515 Records

PubChem

6.3.2 Substances by Category https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 17/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

PubChem

6.4 Entrez Crosslinks

PubMed 17,259 Records

Protein Structures 146 Records

Taxonomy 1 Record

Gene 1 Record

PubChem

6.5 Associated Chemicals

Tryptophan (D);153-94-6

Hazardous Substances Data Bank (HSDB)

Tryptophan (DL); 54-12-6

Hazardous Substances Data Bank (HSDB)

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 18/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

7 Chemical Vendors

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Watanabe Chemical Ind. PubChem SID: 386053749 Purchasable Chemical: G00034

SpiroChem PubChem SID: 373996371 Purchasable Chemical: SPC-g108 (URL not provided...)

Acros Organics PubChem SID: 376168534 Purchasable Chemical: AC140590010

AbaChemScene PubChem SID: 341099716 Purchasable Chemical: CS-W020011

BLD Pharm PubChem SID: 375442094 Purchasable Chemical: BD34769

Sigma-Aldrich PubChem SID: 329751437 Purchasable Chemical: 1700501_USP

Win-Win Chemical PubChem SID: 438516327 Purchasable Chemical: 5944 (URL not provided...)

3WAY PHARM INC PubChem SID: 438551217 Purchasable Chemical: SWOT-43257

Hangzhou APIChem Technology PubChem SID: 92715498 Purchasable Chemical: AC-17050 (URL not provided...)

CAPOT PubChem SID: 152245399 Purchasable Chemical: 10984

LabNetwork, a WuXi AppTec Company PubChem SID: 346584260 Purchasable Chemical: LN00008613

AHH Chemical co.,ltd PubChem SID: 252400153 Purchasable Chemical: MB-00567

Life Chemicals PubChem SID: 315341482 Purchasable Chemical: F0001-2364

Oakwood Products PubChem SID: 377011386 Purchasable Chemical: 102089

TCI (Tokyo Chemical Industry) PubChem SID: 87576460 Purchasable Chemical: T0541

BOC Sciences PubChem SID: 254783793 Purchasable Chemical: 73-22-3

Alfa Aesar PubChem SID: 376195041 Purchasable Chemical: A10230

eNovation Chemicals PubChem SID: 319453021 Purchasable Chemical: D383233

Alfa Chemistry PubChem SID: 347759118 Purchasable Chemical: 73-22-3

Mcule PubChem SID: 166223007 Purchasable Chemical: MCULE-8004234494

LGC Standards PubChem SID: 377008974 Purchasable Chemical: DRE-C17895020

FondChemical Co., Ltd PubChem SID: 384645460 Purchasable Chemical: FDB-1659

Acadechem PubChem SID: 321934370 Purchasable Chemical: ACDS-064120

Sinfoo Biotech PubChem SID: 404826991 Purchasable Chemical: S048463

VladaChem PubChem SID: 329735641 Purchasable Chemical: VL144982

Hairui Chemical PubChem SID: 375638308 Purchasable Chemical: HR134419

AA BLOCKS PubChem SID: 374181849 Purchasable Chemical: AA003R3R https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 19/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Enamine PubChem SID: 334089500 Purchasable Chemical: Z1245635763

OChem PubChem SID: 341833060 Purchasable Chemical: 2893

Debye Scientific Co., Ltd PubChem SID: 202549204 Purchasable Chemical: DB-029986

VWR, Part of Avantor PubChem SID: 384256364 Purchasable Chemical: 200006-766

3B Scientific (Wuhan) Corp PubChem SID: 375135039 Purchasable Chemical: 3B1-01564

abcr GmbH PubChem SID: 316398196 Purchasable Chemical: AB119999

Angene Chemical PubChem SID: 318469191 Purchasable Chemical: AGN-PC-0WADMD

Anward PubChem SID: 160803809 Purchasable Chemical: ANW-36308

China MainChem Co., Ltd PubChem SID: 354702010 Purchasable Chemical: 73-22-3

MolPort PubChem SID: 88837483 Purchasable Chemical: MolPort-001-794-499

DC Chemicals PubChem SID: 350090095 Purchasable Chemical: DCS-083

ChemTik PubChem SID: 162654636 Purchasable Chemical: CTK2H7431

Achemtek PubChem SID: 381357805 Purchasable Chemical: 0101-001288

Alichem PubChem SID: 378043122 Purchasable Chemical: 471002005

Apexmol PubChem SID: 172088542 Purchasable Chemical: AM82273

Ambeed PubChem SID: 376145533 Purchasable Chemical: A317029

Chem-Space.com Database PubChem SID: 434632956 Purchasable Chemical: CSSB00011417517

AK Scientific, Inc. (AKSCI) PubChem SID: 252516106 Purchasable Chemical: HTS001390

MedChemexpress MCE PubChem SID: 381148485 Purchasable Chemical: HY-N0623

Selleck Chemicals PubChem SID: 404639040 Purchasable Chemical: S3987

ChemFaces PubChem SID: 274954748 Purchasable Chemical: CFN90473

ZINC PubChem SID: 255548007 Purchasable Chemical: ZINC83315

Changzhou Highassay Chemical Co., Ltd PubChem SID: 313081375 Purchasable Chemical: my_sub2442 (URL not provided...)

Parchem PubChem SID: 316603695 Purchasable Chemical: 441

Norris Pharm PubChem SID: 383214729 Purchasable Chemical: NSTH-D08541 (URL not provided...)

AKos Consulting & Solutions PubChem SID: 151993471 Purchasable Chemical: AKOS015854052

Achemo Scientific Limited PubChem SID: 312808196 Purchasable Chemical: AC-62341

BerrChem PubChem SID: 174472625 Purchasable Chemical: BR-50074 (URL not provided...)

Yuhao Chemical https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 20/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

PubChem SID: 438468215 Purchasable Chemical: LT7526

Matrix Scientific PubChem SID: 406703623 Purchasable Chemical: 127509

ApexBio Technology PubChem SID: 163632730 Purchasable Chemical: A7403

Paragos PubChem SID: 354337319 Purchasable Chemical: 300141

Aaron Chemicals LLC PubChem SID: 406517433 Purchasable Chemical: AR003RVJ

Chemenu Inc. PubChem SID: 354292850 Purchasable Chemical: CM119384

A2Z Chemical PubChem SID: 251970514 Purchasable Chemical: AZB32727

Lan Pharmatech PubChem SID: 433837872 Purchasable Chemical: LAN-B43221

King Scientific PubChem SID: 163806507 Purchasable Chemical: KSC377I3D

MuseChem PubChem SID: 355176367 Purchasable Chemical: R048596

Hefei Hirisun Pharmatech Co., Ltd PubChem SID: 319433298 Purchasable Chemical: HR013068

CSNpharm PubChem SID: 384653609 Purchasable Chemical: CSN23596

Synblock Inc PubChem SID: 378130593 Purchasable Chemical: SB14997

ACT Chemical PubChem SID: 172438514 Purchasable Chemical: ACT08662 (URL not provided...)

Key Organics/BIONET PubChem SID: 249742566 Purchasable Chemical: STR02722

Glentham Life Sciences Ltd. PubChem SID: 310281481 Purchasable Chemical: GM0674

Activate Scientific PubChem SID: 384417520 Purchasable Chemical: AS33044-2S

Acorn PharmaTech Product List PubChem SID: 329979717 Purchasable Chemical: ACN-033629

BroadPharm PubChem SID: 143503835 Purchasable Chemical: BP-13286

PubChem

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 21/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

8 Drug and Medication Information

8.1 Drug Indication

Tryptophan may be useful in increasing serotonin production, promoting healthy sleep, managing depression by enhancing mental and emotional well-being, managing pain tolerance, and managing weight.

DrugBank

Parenteral nutrition

European Medicines Agency (EMA)

Supplementation of amino-acids where parenteral nutrition is required.

European Medicines Agency (EMA)

8.2 Clinical Trials

8.2.1 ClinicalTrials.gov

ClinicalTrials.gov

8.2.2 EU Clinical Trials Register

EU Clinical Trials Register

8.3 EMA Drug Information

Showing 2 of 4 View More

Disease/Condition Treatment of maple syrup urine disease

Glycine, L-alanine, L-arginine, L-aspartic acid, L-cysteine, L-glutamic acid, L-histidine, L-lysine monohydrate, L-methionine, L-phenylalanine, L-proline, L-serine, L-threonine, L- Active Substance tryptophan, L-tyrosine, taurine

Status of Orphan Positive Designation

Decision Date 2018-10-26

European Medicines Agency (EMA)

Active Substance https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 22/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Therapeutic Area Nutrition

Drug Form Emulsion for infusion

Administration Route Intravenous use

Decision Type W: decision granting a waiver in all age groups for all conditions or indications

Decision Date 2017-06-07

European Medicines Agency (EMA)

8.4 Therapeutic Uses

Tryptophan is a precursor of serotonin. Because CNS depletion of serotonin is considered to be involved in depression, tryptophan has been used in its treatment. Although it has been given alone, evidence of effectiveness is scant and tryptophan has generally been used as adjunctive therapy in depression. It has sometimes been given with pyridoxine and ascorbic acid, which are involved in its metabolism to serotonin Sweetman SC (ed), Martindale: The Complete Drug Reference. London: Pharmaceutical Press (2009), p.427.

Hazardous Substances Data Bank (HSDB)

/EXPTL USE/: Inhibition of Walker 256 intramuscular carcinoma in rats by admin of l-tryptophan. PMID:5446186 Gold J; Oncology 24 (4): 291-303 (1970)

Hazardous Substances Data Bank (HSDB)

(L)-Tryptophan decreases sleep latency and slightly increases sleeping time without altering qualitative characteristics of polygraphic patterns during sleep in normal subjects. In insomniac patients, it increases sleeping time and decreases both sleep latency and number of awakenings. PMID:4935665 Hartmann E et al; Psychopharmacologia 19 (2): 114 (1971)

Hazardous Substances Data Bank (HSDB)

Beneficial effects were observed when L-tryptophan was administered to 2 patients with myoclonus. In each case suspension of methylcellulose and water containing 1 g of (L)-tryptophan/15 mL was prepared and administered orally at a level of 10 g daily in 5 divided doses. Delean J, Richardson JC; Lancet 2 (7940): 870-1 (1975)

Hazardous Substances Data Bank (HSDB)

Some patients with rheumatoid arthritis given tryptophan as an antidepressant had reduced rheumatic symptoms, with recurrence when tryptophan was withdrawn. Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 62

Hazardous Substances Data Bank (HSDB)

In a double-blind study in 5 patients with mania, tryptophan was slightly superior to chlorpromazine. Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 62

Hazardous Substances Data Bank (HSDB)

Tryptophan 500 mg every 6 hr gave useful reduction in migraine symptoms in 4 of 8 patients. Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 62

Hazardous Substances Data Bank (HSDB)

In a double-blind crossover study involving 5 patients with intractable pain, tolerance to the pain relief obtained by central grey stimulation (electrical stimulation of grey matter) was reversed in 4 by concurrent admin of tryptophan 750 mg four times daily. The fifth patient experienced acute gastric pain on ingestion of tryptophan and did not continue the study. Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 62

Hazardous Substances Data Bank (HSDB)

Sleep laboratory and outpatient studies of the hypnotic efficacy of the amino acid L-tryptophan are reviewed, with particular emphasis on evaluation of therapeutic effectiveness in the treatment of insomnia. In younger situational insomniacs, whose sleep problem consists solely of longer than usual sleep latencies, L-tryptophan is effective in reducing sleep onset time on the first night of administration in doses ranging from 1 to 15 g. In more chronic, well established sleep onset insomnia or in more severe insomnias characterized by both sleep onset and sleep maintenance problems, repeated administration of low doses of L-tryptophan over time may be required for therapeutic improvement. In these patients, hypnotic effects appear late in the treatment period or, as shown in some studies, even after discontinuation of treatment. The improvement in sleep measures post-treatment has given rise to use of a treatment regimen known as "interval therapy", in which L-tryptophan treatment alternates with an L-tryptophan-free interval until improvement occurs. The absence of side effects and lack of development of tolerance in long-term use are important factors in the decision to embark upon a trial of L-tryptophan treatment. In addition, L-tryptophan administration is not associated with impairment of visuomotor, cognitive, or memory performance, nor does it elevate threshold for arousal from sleep. PMID:3090582 Schneider-Helmert D, Spinweber CL; Psychopharmacology 89 (1): 1-7 (1986).

Hazardous Substances Data Bank (HSDB)

Abnormal metabolism of tryptophan may occur in patients with pyridoxine deficiency and tryptophan is thus sometimes given with pyridoxine supplements. Sweetman SC (ed), Martindale: The Complete Drug Reference. London: Pharmaceutical Press (2009), p.427.

Hazardous Substances Data Bank (HSDB)

/EXPTL USE/: Melatonin (MT) and its precursor L-tryptophan (Trp) are implicated in the protection of gastric mucosa against noxious agents. ... Studies in animals showed that both MT and Trp given intragastrically prevents the formation of gastric mucosal lesions induced by aspirin (ASA). The aim of /this/ study was to determine the influence of MT and Trp given orally to https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 23/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

healthy humans on gastric mucosal lesions induced by ASA. The present study included 21 healthy, Hp-negative male volunteers with intact gastro-duodenal mucosa aging 20-50 yr. They were divided in 3 groups; group 1: 7 volunteers receiving daily 2 x 1g ASA (Polfa, Rzeszow) during 11 days; group 2: 7 healthy volunteers receiving 2x1 g ASA and MT (Lekam, Zakroczyn) (5 mg 30 min prior to ASA) during 11 days and group 3: 7 healthy volunteers receiving 2x1 g ASA and Trp (Ardeytropin, Germany) (0.5 g 30 min prior to ASA) during 11 days. Mucosal damage was evaluated at 3(rd), 7(th) and 11(th) days of ASA administration by endoscopy using Lanza score. Plasma melatonin was measured using RIA and gastric mucosal generation of PGE(2) was assessed also by RIA. ASA caused marked mucosal injury at all days of its administration except day 11(th) when only moderate lesions were evident. Pretreatment with MT or Trp alone was accompanied by a significant decrease in gastric mucosal lesion score. Gastric mucosal generation of PGE(2) was suppressed by about 90% in subjects treated with ASA without or with MT or Trp. We concluded that: MT and its precursor Trp significantly attenuate gastric mucosal lesions induced by aspirin. The action of Trp may be be mediated by MT produced in gastrointestinal tract from Trp. The gastroprotective action of MT and Trp is independent on gastric mucosal PGE2 generation. Konturek PC et al; J Physiol Pharmacol 59 (2): 67-75 (2008). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=18812629

Hazardous Substances Data Bank (HSDB)

8.5 Drug Warnings

Since serotonin plays a role in inducing and maintaining sleep, l-tryptophan has been administered orally to increase brain levels of serotonin. Although a dose of 1 g significantly decreased sleep latency and total time awake without altering sleep patterns, the hypnotic action is observed only during the early part of the sleep cycle, is unpredictable, and is not characterized by a satisfactory dose-response relationship. Because the hypnotic action has not been confirmed in other studies, this use of l-tryptophan must be considered investigational and the drug is not recommended in routine clinical practice. In order to avoid central serotonergic toxicity, tryptophan should not be used in patients also receiving a monoamine oxidase inhibitor or the serotonin uptake inhibitor, fluoxetine (Prozac). American Medical Association. AMA Drug Evaluations Annual 1991. Chicago, IL: American Medical Association, 1991., p. 215

Hazardous Substances Data Bank (HSDB)

Tryptophan-containing products have been associated with the eosinophilia-myalgia syndrome. Other adverse effects that have been reported include nausea, headache, lightheadedness, and drowsiness. Sweetman SC (ed), Martindale: The Complete Drug Reference. London: Pharmaceutical Press (2009), p.427.

Hazardous Substances Data Bank (HSDB)

An increased incidence of bladder tumours has been reported in mice given l-tryptophan orally as well as in cholesterol pellets embedded in the bladder lumen. However, there was no increase in tumour incidence when only high-dose, oral tryptophan was given. Sweetman SC (ed), Martindale: The Complete Drug Reference. London: Pharmaceutical Press (2009), p.427.

Hazardous Substances Data Bank (HSDB)

Tryptophan has been associated with eosinophilia-myalgia syndrome; caution is advised in patients receiving the drug who develop some, but not all, of the symptoms of this syndrome. It should not be used in those with a history of eosinophilia-myalgia syndrome associated with tryptophan treatment. Sweetman SC (ed), Martindale: The Complete Drug Reference. London: Pharmaceutical Press (2009), p.427.

Hazardous Substances Data Bank (HSDB)

For more Drug Warnings (Complete) data for (L)-Tryptophan (7 total), please visit the HSDB record page.

Hazardous Substances Data Bank (HSDB)

8.6 Drug Idiosyncrasies

The concomitant admin of tryptophan and a monoamine oxidase inhibitor may provoke a reaction likened to inebriation and may enhance the effects of the monoamine oxidase inhibitor. If concomitant admin is desired the initial dose of tryptophan should be 500 mg daily, gradually increased after one week. Such treatment should be initiated in hospital. Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 61

Hazardous Substances Data Bank (HSDB)

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 24/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

9 Food Additives and Ingredients

9.1 FDA Substances Added to Food

Substance L-TRYPTOPHAN

Used for (Technical Effect) NUTRIENT SUPPLEMENT

Document Number (21 CFR) 172.320

FDA Center for Food Safety and Applied Nutrition (CFSAN)

Source: FDA Center for Food Safety and Applied Nutrition (CFSAN) Record Name: L-TRYPTOPHAN URL: https://www.cfsanappsexternal.fda.gov/scripts/fdcc/index.cfm?set=FoodSubstances&id=TRYPTOPHAN Description: The Substances Added to Food (formerly EAFUS) inventory includes information on food additives, color additives, Generally Recognized As Safe (GRAS) and prior-sanctioned substances. https://www. cfsanappsexternal.fda.gov/scripts/fdcc/index.cfm?set=FoodSubstances License Note: Unless otherwise noted, the contents of the FDA website (www.fda.gov), both text and graphics, are not copyrighted. They are in the public domain and may be republished, reprinted and otherwise used freely by anyone without the need to obtain permission from FDA. Credit to the U.S. Food and Drug Administration as the source is appreciated but not required. License URL: https://www.fda.gov/about-fda/about-website/website-policies#linking

9.2 Associated Foods

Angelica Yau choy Lantern fruit German camomile Black mulberry Passion fruit Pine nut Almond Watercress Winte Lemon verbena Water spinach White bread Lemon balm Nutmeg Pepper (Spice) Peach Rosemary Rye Parsnip Lovage Flaxseed Mexican oregano Mentha Sweet basil Custard apple Wild celery Peanut Burdo Dill Black raisin Chineese plum Cape gooseberry Cashew nut Pineapple Guava Rubus (Blackberry, Raspberry) Sesam Avocado Pistachio Cannellini bean Green plum Herbal tea Orange mint Evening primrose Pomegranate Cloudberry Garde Parsley Common pea Wampee Taco shell Cornmint Olive Red raspberry Cherr Green lentil Scarlet bean Purslane Pear Pitaya Tostada shell Spearmint Sweet marjoram Black raspberry Garde Cubanelle pepper Lima bean Prunus (Cherry, Plum) Radish Lichee Peppermint Pot marjoram Eggpl Acorn squash Goji Common bean Apricot Garden rhubarb Sorrel Lupine Medlar Common oregano Potato Iceberg lettuce Monk fruit Date Sweet cherry Blackcurrant Common sage Bitter gourd Rice Japanese sea bass Cantaloupe melon Apple Black chokeberry Sour cherry Redcurrant Black elderberry Rowa Mulberry Millet Pea shoots Hawthorn Mango Anise European plum Gooseberry Summer savory Sorgh Poppy

FooDB

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 25/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

10 Pharmacology and Biochemistry

10.1 Pharmacology

Tryptophan is critical for the production of the body's proteins, enzymes and muscle tissue. It is also essential for the production of niacin, the synthesis of the neurotransmitter serotonin and melatonin. Tryptophan supplements can be used as natural relaxants to help relieve insomnia. Tryptophan can also reduce anxiety and depression and has been shown to reduce the intensity of migraine headaches. Other promising indications include the relief of chronic pain, reduction of impulsivity or mania and the treatment of obsessive or compulsive disorders. Tryptophan also appears to help the immune system and can reduce the risk of cardiac spasms. Tryptophan deficiencies may lead to coronary artery spasms. Tryptophan is used as an essential nutrient in infant formulas and intravenous feeding. Tryptophan is marketed as a prescription drug (Tryptan) for those who do not seem to respond well to conventional antidepressants. It may also be used to treat those afflicted with seasonal affective disorder (a winter-onset depression). Tryptopan serves as the precursor for the synthesis of serotonin (5-hydroxytryptamine, 5-HT) and melatonin (N-acetyl-5-methoxytryptamine).

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NCI Thesaurus (NCIt)

10.2 MeSH Pharmacological Classification

Antidepressive Agents, Second-Generation

A structurally and mechanistically diverse group of drugs that are not tricyclics or monoamine oxidase inhibitors. The most clinically important appear to act selectively on serotonergic systems, especially by inhibiting serotonin reuptake. (See all compounds classified as Antidepressive Agents, Second-Generation.)

MeSH

10.3 ATC Code

N - Nervous system

N06 - Psychoanaleptics

N06A - Antidepressants

N06AX - Other antidepressants N06AX02 - Tryptophan

WHO Anatomical Therapeutic Chemical (ATC) Classification

10.4 Bionecessity

... Skin is an optically inhomogeneous medium; reflection, refraction, scattering, and absorption all modify the radiation that reaches deeper structures. Important UV absorbers within the epidermis incl melanin, which varies greatly in content and location between individuals and races; urocanic acid, a deamination product of histidine found in sweat; and for shorter wavelengths, proteins containing tryptophan and tyrosine. The net optical effect is that shorter wavelengths are selectively absorbed in the superficial layers, although a biologically significant amt of UV-B reaches the dermis ... . Amdur, M.O., J. Doull, C.D. Klaasen (eds). Casarett and Doull's Toxicology. 4th ed. New York, NY: Pergamon Press, 1991., p. 476

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An essential amino acid for human development; precursor of serotonin. O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1682

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...Tryptophan is a significant precursor of niacin for humans. It is for this reason that high corn diets result in clinical deficiency (pellagra) of niacin, corn being particularly deficient in tryptophan. Furia, T.E. (ed.). CRC Handbook of Food Additives. 2nd ed. Cleveland: The Chemical Rubber Co., 1972., p. 89

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Corn and cereal grains contain fairly adequate quantities of niacin, but the vitamin is in a bound and unavailable form. They are also low in tryptophan. The combination of low tryptophan and unavailable dietary niacin results in a niacin deficiency. In current feeding practice in intensive agriculture situations, niacin or tryptophan should be added to high-concentrate diets of poultry and pigs. Booth, N.H., L.E. McDonald (eds.). Veterinary Pharmacology and Therapeutics. 5th ed. Ames, Iowa: Iowa State University Press, 1982., p. 637

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Penetrating keratoplasty has been the mainstay for the treatment of blindness and is the most common form of tissue transplantation worldwide. Due to significant rates of rejection, treatment of immunological transplant reactions is of wide interest. Recently in a mouse model, the overexpression of indoeleamine 2,3 dioxigenase (IDO) was led to an extension in corneal allograft survival. L-kynurenine is a tryptophan metabolite, which may render activated T-cells apoptotic and therefore might modulate an allogenous transplant reaction. ... The expression levels of IDO in human corneal endothelial cells (HCECs) and downstream tryptophan/kynurenine mechanisms in cell culture /were analyzed/. ... IDO and an associated tryptophan/kynurenine transporter protein exchange mechanism /were/ upregulated by inflammatory cytokines in HCECs. The inhibition of T-cell proliferation might depend on rapid delivery of the tryptophan metabolite, L-kynurenine, to the local corneal environment. Microarray analysis gives evidence that the large amino acid transporter 1 (LAT1) transporter protein is responsible for this mechanism. CONCLUSIONS: /The/ data support that adequate levels of functional L-kynurenine might contribute to the maintenance of a relative immune privilege in the ocular anterior chamber, thereby contributing to the preservation of corneal allogeneic cells. Serbecic N et al; Molecular Vision 15: 1312-24 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19597571 https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 26/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

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Calculation of Estimated Average Requirement (EAR) and Recommended Dietary Allowance (RDA) for Tryptophan for Children Ages 7 Months Through 18 Years

Age and Gender Maintenance (mg/kg/day) Amino Acid Deposition (mg/kg/day) Total = EAR (mg/kg/day) RDA (mg/kg/day)

7-12 months, Boys, Girls 4 3 9 13

1-3 years, Boys, Girls 4 1 6 8

4-8 years, Boys, Girls 4 1 5 6

9-13 years, Boys 4 1 5 6

9-13 years, Girls 4 <0.5 5 6

14-18 years, Boys 4 <0.5 5 6

14-18 years, Girls 4 <0.5 4 5

NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 672-679, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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Older views of the nutritional classification of amino acids categorized them into two groups: indispensable (essential) and dispensable (nonessential). The nine indispensable amino acids /(histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine)/ are those that have carbon skeletons that cannot be synthesized to meet body needs from simpler molecules in animals, and therefore must be provided in the diet. ...The definition of dispensable amino acids has become blurred as more information on the intermediary metabolism and nutritional characteristics of these compounds has accumulated. ... Dispensable amino acids /have been divided/ into two classes: truly dispensable and conditionally indispensable. Five amino acids /(alanine, aspartic acid, asparagine, glutamic acid, and serine)/ are termed dispensable as they can be synthesized in the body from either other amino acids or other complex nitrogenous metabolites. In addition, six other amino acids, including /arginine, cysteine, glutamine, glycine, proline, and tyrosine/, are conditionally indispensable as they are synthesized from other amino acids or their synthesis is limited under special pathophysiological conditions. This is even more of an issue in the neonate where it has been suggested that only alanine, aspartate, glutamate, serine, and probably asparagine are truly dietarily dispensable. /Amino acids/ NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 593-594, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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The term conditionally indispensable recognizes the fact that under most normal conditions the body can synthesize these amino acids to meet metabolic needs. However, there may be certain physiological circumstances: prematurity in the young infant where there is an inadequate rate at which cysteine can be produced from methionine; the newborn, where enzymes that are involved in quite complex synthetic pathways may be present in inadequate amounts as in the case of arginine, which results in a dietary requirement for this amino acid; or pathological states, such as severe catabolic stress in an adult, where the limited tissue capacity to produce glutamine to meet increased needs and to balance increased catabolic rates makes a dietary source of these amino acids required to achieve body nitrogen homeostasis. The cells of the small intestine become important sites of conditionally indispensable amino acid, synthesis, with some amino acids (e.g., glutamine and arginine) becoming nutritionally indispensable under circumstances of intestinal metabolic dysfunction. /Amino acids/ NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 594, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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When diets high or low in protein are given, there is a gain or loss of body protein over the first few days, before re-equilibration of protein intake with the rates of oxidation and excretion. This phenomenon has led to the concept of a "labile protein reserve," which can be gained or lost from the body as a short-term store for use in emergencies or to take account of day-to-day variations in dietary intake. Studies in animals have suggested that this immediate labile protein store is contained in the liver and visceral tissues, as their protein content decreases very rapidly during starvation or protein depletion (by as much as 40 percent), while skeletal muscle protein drops much more slowly. During this situation, protein breakdown becomes a source of indispensable amino acid needs for synthesis of proteins critical to maintaining essential body function. This labile protein reserve in humans is unlikely to account for more than about 1 percent of total body protein. Thus, the immediately accessible stores of protein (which serve as the source of indispensable amino acids and amino nitrogen) cannot be considered in the same light as the huge energy stores in the form of body fat; the labile protein reserve is similar in weight to the glycogen store. /Amino acids/ NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 595, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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Dietary protein is not only needed for maintaining protein turnover and the synthesis of physiologically important products of amino acid metabolism but is, of course, laid down as new tissue. /Amino acids/ NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 598, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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The adequate intake (AI) for infants 0 through 6 months of age is based on the average volume of milk intake of 0.78 L/day, and the mean indispensable amino acid content of human milk. Table: Adequate Intake (AI) for Infants

0-6 months 214 mg/day or 36 mg/kg/day of histidine

529 mg/day or 88 mg/kd/day of isoleucine

938 mg/day or 156 mg/kg/day of leucine

640 mg/day or 107 mg/kg/day of lysine

353 mg/day or 59 mg/kg/day of methionine + cysteine

807 mg/day or 135 mg/kg/day of phenylalanine + tyrosine

436 mg/day or 73 mg/kg/day of threonine

167 mg/day or 28 mg/kg/day of tryptophan

519 mg/day or 87 mg/kg/day of valine

NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 663, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 27/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Estimated Average Requirements (EAR) for Adults 19 years and older. 11 mg/kg/day of histidine; 15 mg/kg/day of isoleucine; 34 mg/kg/day of leucine; 31 mg/kg/day of lysine; 15 mg/kg/day of methionine + cysteine; 27 mg/kg/day of phenylalanine + tyrosine; 16 mg/kg/day of threonine; 4 mg/kg/day of tryptophan; 19 mg/kg/day of valine. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 679, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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Recommended Dietary Allowance (RDA) for Adults 19 years and older. 14 mg/kg/day of histidine; 19 mg/kg/day of isoleucine; 42 mg/kg/day of leucine; 38 mg/kg/day of lysine; 19 mg/kg/day of methionine + cysteine; 33 mg/kg/day of phenylalanine + tyrosine; 20 mg/kg/day of threonine; 5 mg/kg/day of tryptophan; 24 mg/kg/day of valine. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 680, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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There are essentially no data with regard to amino acid requirements during pregnancy, so it is generally assumed that indispensable amino acid needs increase in proportion to the increased protein needs during pregnancy. Estimated Average Requirement (EAR) for Pregnancy For all ages. 15 mg/kg/day of histidine; 20 mg/kg/day of isoleucine; 45 mg/kg/day of leucine; 41 mg/kg/day of lysine; 20 mg/kg/day of methionine + cysteine; 36 mg/kg/day of phenylalanine + tyrosine; 21 mg/kg/day of threonine; 5 mg/kg/day of tryptophan; 25 mg/kg/day of valine. The recommended dietary allowance (RDA) for amino acids for pregnancy is set by increasing the EAR by the variation in protein derived for adults ages 19 years and older (1.24 x EAR) and rounded to nearest whole number. RDA for Pregnancy For all ages. 18 mg/kg/day of histidine; 25 mg/kg/day of isoleucine; 56 mg/kg/day of leucine; 51 mg/kg/day of lysine; 25 mg/kg/day of methionine + cysteine; 44 mg/kg/day of phenylalanine + tyrosine; 26 mg/kg/day of threonine; 7 mg/kg/day of tryptophan; 31 mg/kg/day of valine. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 680-681, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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There are essentially no data with regard to amino acid requirements during lactation, so it is generally assumed that indispensable amino acid needs will increase over the nonlactating needs by the amount of amino acids found in human milk. Estimated Average Requirement (EAR) for Lactation, For all ages. 15 mg/kg/d of histidine; 24 mg/kg/day of isoleucine; 50 mg/kg/day of leucine; 42 mg/kg/day of lysine; 21 mg/kg/day of methionine + cysteine; 41 mg/kg/day of phenylalanine + tyrosine; 24 mg/kg/day of threonine; 7 mg/kg/day of tryptophan; 28 mg/kg/day of valine. The recommended dietary allowance (RDA) for amino acids for lactation is set by assuming the same coefficient of variation (CV) as that for total protein for lactation, 12%. The RDA is defined as the EAR plus twice the assumed CV to cover the needs of 97 to 98% of the individuals in the group. Therefore, for amino acids the RDA is 124% of the EAR for adolescents and adults. The calculated RDA in mg/kg of body weight/day is rounded. RDA for Lactation, For all ages. 19 mg/kg/day of histidine; 30 mg/kg/day of isoleucine; 62 mg/kg/day of leucine; 52 mg/kg/day of lysine; 26 mg/kg/day of methionine + cysteine; 51 mg/kg/day of phenylalanine + tyrosine; 30 mg/kg/day of threonine; 9 mg/kg/day of tryptophan; 35 mg/kg/day of valine. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 681-682, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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/An/ important factor that influences the nutritional value of a protein source is the relative content and metabolic availability of the individual indispensable amino acids. If the content of a single indispensable amino acid in the diet is less than the individual's requirement, then it will limit the utilization of other amino acids and thus prevent normal rates of protein synthesis even when the total nitrogen intake level is adequate. Thus, the "limiting amino acid" will determine the nutritional value of the total nitrogen or protein in the diet. ... The concept of the limiting amino acid has led to the practice of amino acid (or chemical) scoring, whereby the indispensable amino acid composition of the specific protein source is compared with that of a reference amino acid composition profile. ... The nutritional implications of these differences in the amino acid content of different proteins or mixtures of proteins can be evaluated by comparing the amino acid composition of the protein source with a suitable reference amino acid pattern. /Amino acids/ NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 685-686, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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Proposed Amino Acid Scoring Patterns for Infants, Preschool Children, and Adults Based on Estimated Requirements for Protein and Indispensable Amino Acids.

Infants (mg/g Preschool Children (1-3 years) (mg/g Preschool Children (1-3 years) (mg/g Adults (18+ years) (mg/g Adults (18+ years) (mg/g Amino Acid protein) protein) N) protein) N)

Histidine 23 18 114 17 104

Isoleucine 57 25 156 23 142

Leucine 101 55 341 52 322

Lysine 69 51 320 47 294

Methionine + cysteine 38 25 156 23 142

Phenylalanine + 87 47 291 41 256 tyrosine

Threonine 47 27 170 24 152

Tryptophan 18 7 43 6 38

Valine 56 32 199 29 180

NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 687, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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Summary FNB/IOM 2002 Amino Acid Scoring Pattern for Use in Children >/= 1 Year of Age and in All Other Older Age Groups

Amino Acid mg/g Protein mg/g N

Histidine 18 114

Isoleucine 25 156

Leucine 55 341

Lysine 51 320

Methionine + cysteine 25 156

Phenylalanine + tyrosine 47 291

Threonine 27 170 https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 28/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Amino Acid mg/g Protein mg/g N

Tryptophan 7 43

Valine 32 199

NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 689, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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...This study evaluated the impact of a reduction of serotonergic stores induced by chronic tryptophan (TRP) depletion on various bone parameters in growing rats. For this purpose rats received a TRP-free diet for 60 days. Bone mass, mineral content and density were measured by DXA and by pQCT in the appendicular skeleton. Bone metabolic markers included urinary deoxypyridinoline and serum osteocalcin measurements. IGF-I levels were also evaluated. In TRP-free diet rats, ... a decrease in body weight, a delayed femoral bone growth and bone mineral content as measured by DXA /were found/. pQCT analysis showed that these effects were related to a reduction of both cortical and trabecular bone and are associated with a reduction of bone strength. These effects are due to a negative shift in the balance between bone formation and resorption with a significant decrease in bone formation as evidenced by a reduction both in osteocalcin and IGF-I levels... Sibilia V et al; J Cell Biochem 107 (5): 890-8 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19459167

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The depletion of systemic tryptophan is an important tool to study the effects of reduced 5-HT on cognition. Indeed, previous reports indicated that acute depletion of TRP leads to a memory impairment in human subjects and rodents. From the view of nutrition, it is important to investigate the effects of chronic limitation of L-tryptophan (TRP) on learning and memory formation. This study examined the effects of chronic consumption of a low TRP diet on memory formation in mice. Specifically, ... the ability to form contextual fear, cued fear, conditioned taste aversion, and spatial memories /was assessed/in mice fed a TRP-limited diet for at least 1 month. TRP-limited mice showed impaired formation of contextual fear memory that is hippocampus- dependent. In contrast, these mice showed normal hippocampus-dependent spatial memory in the Morris water maze test, as well as in cued fear and conditioned taste aversion memories, which are amygdala-dependent memory processes. Thus, dietary TRP restriction appears to result in selective impairments in hippocampus-dependent contextual fear memory formation in mice. Uchida S et al; Brain Res 1149: 149-56 (2007). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=17382305

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An ontogenetic study was designed on developing rats in uterus of mothers tryptophan deprived at day 1 (exp. 1) and day 14.5 (exp. 2) of conception to verify the supposed determining role of the serotoninergic system (SS) in sexual differentiation in mammals. Tryptophan-free feeding was pursued uninterruptedly in the litter after birth, during lactation and post-natal development. Tryptophan-free pregnant rats were obtained by exclusion of tryptophan sources from chow. In both exp. 1 and exp. 2, the litter showed at birth a significant physical under evolution that worsened, during post-natal development, to a much more marked dwarfism in exp. 1 pups. Growth hormone concentrations in both sexes of dwarf rats were lower than that in the control rats. At 30 days post-natal age, whereas exp. 1 female rats showed a right-timed onset of puberty, no descensus of testes could be observed in male rats of same experiment. Dwarf male rats showed an evident hypotrophy of the whole reproductive apparatus. In histological examination of testes, neither spermatogenesis nor Leydig cells have been observed. Moreover, dwarf female rats showed a pronounced hypotrophy of reproductive organs, but a normal puberal status pattern was evident. In exp. 2, litters showed a less pronounced dwarfism, but a normal right-timed onset of puberty in both male and female rats. Data indicate that role of tryptophan in physical and sexual maturation in both male and female rats is essential. Imbesi R et al; Anatomia, Histolog, Embryol 38 (5): 361-9 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19769571

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Previous studies suggest an important role for serotonergic (5-HT) modulation of the acoustic startle reflex (ASR) and prepulse inhibition (PPI). Acute challenge of brain serotonin by means of tryptophan depletion test (TDT) represents an established human challenge tool for temporary reduction of tryptophan (-TRP) levels and central nervous serotonin. Under these experimental conditions, PPI was found attenuated in males, but greater biochemical effects of TDT in the central nervous system of females are known. Therefore, in order to explore influence of 5-HT on various standard startle parameters in females, 16 young healthy females participated in a double-blind, cross-over TDT study. Acoustic stimuli were presented in 15 pulse-alone trials (100 dB, 40 ms) randomly followed by 25 pulse-alone or prepulse (70 dB, 30 ms; 120 ms interval) trials alongside electromyographic eyeblink recordings and mood state assessments. During 81% depletion of free plasma TRP, mean ASR magnitudes were significantly reduced compared to control (+TRP) condition while there were no differences in habituation or PPI nor did startle parameters correlate with mood states. Changes of plasma TRP and mood states correlated in tendency negatively in (-TRP) for depression and positively in (+TRP) for fatigue. In conclusion, this first study of startle parameters after TDT in a homogenous female population demonstrates that depletion of brain 5-HT in women only influences ASR. Norra C et al; Eur Arch Psych Clin Neurosci 258 (1): 1-9 (2008). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=17902001

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Research on 5-HT-functioning in adult patients and healthy subjects using rapid tryptophan depletion (RTD) has indicated weak but stable effects on mood ratings. Altered mood in children and adolescents with attention-deficit/hyperactivity disorder (ADHD) can confound the differential diagnosis between severe ADHD and mood disorders such as pediatric bipolar disorder. /This/ study investigated the effects of RTD induced lowered central nervous 5-HT-levels on mood self-ratings in ... 17 boys with ADHD ... . They were administered RTD within an amino acid drink lacking tryptophan, thus lowering central nervous 5-HT-synthesis. On another day they received a placebo. Self-rated mood was assessed on both days at baseline conditions and at three different post-drink time-points. RTD had no clear effect on mood within the whole sample. Low scorers on venturesomeness were more strongly affected by RTD in terms of feelings of inactivity and negative feelings compared to high venture patients... Zepf FD et al; Hum Psychopharmacol 24 (2): 87-94 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19226535

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The essential amino acid tryptophan is the precursor of the neurotransmitter serotonin. By depleting the body of tryptophan, brain tryptophan and serotonin levels are temporarily reduced. ... Several experiments are described in which dose and treatment effects of acute tryptophan depletion (ATD) using a gelatin-based protein-carbohydrate mixture were studied in male and female Wistar rats. Two or three doses of tryptophan depleting mixture resulted in 65-70% depletion after 2-4 hr in males. ATD effects were similar in females, although females may return to baseline levels faster. Treatment effects after four consecutive days of ATD were similar to the effects of 1 day of treatment. Object recognition memory was impaired 2, 4, and 6 hr after the first of two doses of ATD, suggesting that the central effects occurred rapidly and continued at least 6 hr, in spite of decreasing treatment effects on plasma tryptophan levels at that time point... Jans LAW et al; Amino Acids 37 (2): 349-57 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=18683016

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/This/ study investigated the effects of rapid tryptophan depletion (RTD) and the ensuing reduction of central nervous levels of serotonin (5-HT) on reactive aggression with respect to personality factors comprising aspects of trait-impulsivity and -aggression in boys with attention-deficit/hyperactivity-disorder (ADHD). Twenty-two male adolescent patients with ADHD received the RTD test on one day, and, on another day a tryptophan balanced placebo in a double-blind within-subject crossover design. Impulsive personality factors and trait-impulsivity were assessed in advance of the study. Aggression was provoked using a competitive reaction time game 270 min after RTD/placebo intake. RESULTS: RTD had a significant effect on increased aggressive behavior with which low-grade impulsive patients responded. High-grade impulsive patients were not affected by RTD or even responded with increased aggressive behaviour https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 29/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

while receiving placebo treatment. CONCLUSIONS: The ... study supports the hypothesis that 5-HT functioning in ADHD patients influences reactive aggression depending on aspects of trait- impulsivity... Zepf FD et al; Hum Psychopharmacol 23 (1): 43-51 (2008). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=17926336

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Polymorphism at the serotonin transporter linked polymorphic region (5-HTTLPR) has been associated with neuroticism, increased risk for affective disorders and greater vulnerability to mood change following serotonin (5-HT) depletion. The aim of the present study was to investigate whether the cognitive effects of 5-HT depletion were differentially affected by genotype at the 5- HTTLPR polymorphism, using neuropsychological measures of memory and attention. ... The acute tryptophan depletion (ATD) technique /was used/ to temporarily reduce 5-HT synthesis in two groups of healthy volunteers pre-selected on the basis of 5-HTTLPR genotype, 15 of the ll genotype and 15 of the ss genotype, in a double-blind, placebo-controlled crossover design. As expected, ATD resulted in a robust reduction in plasma tryptophan concentration in both genotype groups. However, the genotype groups differed in terms of the effect of ATD on cognitive performance. The ss genotype group showed impaired verbal recall following depletion, while episodic memory was unimpaired by ATD in the ll genotype group. Averaging across depletion condition, the ss genotype group outperformed the ll genotype group on tests of episodic memory and attention. Neither group was significantly affected by ATD on measures of emotional state. These data confirm previous reports that ss individuals are particularly vulnerable to 5-HT depletion, but extend these findings to the cognitive domain. The unexpected finding that ss volunteers showed improved memory and attention relative to ll volunteers suggests a possible evolutionary advantage to possession of the s allele, which may offset the disadvantage of vulnerability to depression following stressful life events. Roiser JP et al; Int J Neuropsychopharmacol 10 (4): 449-61 (2007). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16893493

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Healthy human subjects without a personal or family history of affective disorder were assessed using a computerized decision making/gambling task and the CANTAB ID/ED attentional set- shifting task under rapid tryptophan depletion(Trp)-depleted (n=17; nine males and eight females) or control (n=15; seven males and eight females) conditions, in a double-blind, randomized, parallel-group design. There was no significant effect of RTD on set shifting, reversal learning, risk taking, impulsivity, or subjective mood. However, RTD significantly altered decision making such that depleted subjects chose the more likely of two possible outcomes significantly more often than controls. This is in direct contrast to the previous report that subjects chose the more likely outcome significantly less often following RTD... Talbot PS et al; Neuropsychopharmacol 31 (7): 1519-25 (2006). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16319909

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The use-dependent specification of neural circuits occurs during post-natal development with a conspicuous influence of environmental factors, such as malnutrition that interferes with the major steps of brain maturation. Serotonin (5-HT), derived exclusively from the essential aminoacid tryptophan, is involved in mechanisms of development and use-dependent plasticity of the central nervous system. We studied the effects of the nutritional restriction of tryptophan in the plasticity of uncrossed retinotectal axons following a retinal lesion to the contralateral retina during the critical period in pigmented rats. Litters were fed through their mothers with a low tryptophan content diet, based on corn and gelatin, a complemented diet with standard tryptophan requirements for rodents or standard laboratory diet. The results suggest a marked reduction in the plasticity of intact axons into denervated territories in the tryptophan restricted group in comparison to control groups. Tryptophan complementation between PND10-21 completely restored retinotectal plasticity. However, the re-introduction of tryptophan after the end of the critical period (between PND28-P41) did not restore the sprouting ability of uncrossed axons suggesting a time-dependent effect to the reversion of plasticity deficits. Tryptophan- restricted animals showed a reduced activity of matrix metalloproteinase-9 and altered expressions of phosphorylated forms of ERK1/2 and AKT. /These/results demonstrate the influence of this essential aminoa cid as a modulator of neural plasticity during the critical period through the reduction of serotonin content which alters plasticity-related signaling pathways and matrix degradation. Penedo LA et al; Exptl Neurol 217 (1): 108-15 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19416666

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Adaptive social behavior often necessitates choosing to cooperate with others for long-term gains at the expense of noncooperative behaviors giving larger immediate gains. Although little is know about the neural substrates that support cooperative over noncooperative behaviors, recent research has shown that mutually cooperative behavior in the context of a mixed-motive game, the Prisoner's Dilemma (PD), is associated with increased neural activity within reinforcement circuitry. Other research attests to a role for serotonin in the modulation of social behavior and in reward processing. ... This study ... used a within-subject, crossover, double-blind design to investigate performance of an iterated, sequential PD game for monetary reward by healthy human adult participants following ingestion of an amino-acid drink that either did (T+) or did not (T-) contain l-tryptophan. Tryptophan depletion produced significant reductions in the level of cooperation shown by participants when playing the game on the first, but not the second, study days. This effect was accompanied by a significantly diminished probability of cooperative responding given previous mutually cooperative behavior. These data suggest that serotonin plays a significant role in the acquisition of socially cooperative behavior in human adult participants, and suggest novel hypotheses concerning the serotonergic modulation of reward information in socially cooperative behavior in both health and psychiatric illness. Wood RM et al; Neuropsychopharm 31 (5): 1075-84 (2006). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16407905

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Acute tryptophan depletion (ATD) can be used to decrease serotonin levels in the brain. Traditionally, ATD has been established by administering amino acid (AA) mixtures and studies using this method showed that serotonin is involved in learning and memory processes. This study used a recently developed gelatin-based protein drink to examine whether it 1) is superior to the traditional AA method in controlling the tryptophan levels in the placebo condition, 2) impairs long-term memory and 3) differentially affects episodic and spatial memory. Sixteen healthy subjects participated in a double-blind, placebo-controlled study. Memory was assessed using a visual verbal learning test and an object relocation task (spatial memory). Tryptophan ratio significantly decreased after ATD and did not significantly increase in the placebo condition. Delayed recall in the verbal learning test and delayed relocation of objects to positions in the spatial task were impaired after ATD. Spatial short-term memory, however, improved. The current results indicate that the tryptophan levels were essentially neutral in the placebo condition compared with those in the traditional AA mixture. /This/ study provides further evidence that impairment in long-term episodic and elementary spatial memory after ATD is related to lowered tryptophan levels in plasma. Sambeth A et al; J Psychopharmacol 23 (1) 56-64 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=18515454

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10.5 Absorption, Distribution and Excretion

(L)-Tryptophan with plant oils in soft gelatin capsules permitted lower dosage than with usual dosage form. Max of free tryptophan in serum was achieved in 1st hr whereas 4-5 times as much would be required with tablets or hard gelatin capsules. Klosa J; Ger Offen Patent NO 2824362 12/13/79

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Absorption and Fate. Tryptophan is readily absorbed from the gastro-intestinal tract. Tryptophan is extensively bound to serum albumin. It is metabolized to serotonin and other metabolites, incl kynurenine derivatives, and excreted in the urine. Pyridoxine and ascorbic acid appear to be concerned in its metabolism. Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 61

Hazardous Substances Data Bank (HSDB) https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 30/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Although the free amino acids dissolved in the body fluids are only a very small proportion of the body's total mass of amino acids, they are very important for the nutritional and metabolic control of the body's proteins. ... Although the plasma compartment is most easily sampled, the concentration of most amino acids is higher in tissue intracellular pools. Typically, large neutral amino acids, such as leucine and phenylalanine, are essentially in equilibrium with the plasma. Others, notably glutamine, glutamic acid, and glycine, are 10- to 50-fold more concentrated in the intracellular pool. Dietary variations or pathological conditions can result in substantial changes in the concentrations of the individual free amino acids in both the plasma and tissue pools. /Amino acids/ NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 596, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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After ingestion, proteins are denatured by the acid in the stomach, where they are also cleaved into smaller peptides by the enzyme pepsin, which is activated by the increase in stomach acidity that occurs on feeding. The proteins and peptides then pass into the small intestine, where the peptide bonds are hydrolyzed by a variety of enzymes. These bond-specific enzymes originate in the pancreas and include trypsin, chymotrypsins, elastase, and carboxypeptidases. The resultant mixture of free amino acids and small peptides is then transported into the mucosal cells by a number of carrier systems for specific amino acids and for di- and tri-peptides, each specific for a limited range of peptide substrates. After intracellular hydrolysis of the absorbed peptides, the free amino acids are then secreted into the portal blood by other specific carrier systems in the mucosal cell or are further metabolized within the cell itself. Absorbed amino acids pass into the liver, where a portion of the amino acids are taken up and used; the remainder pass through into the systemic circulation and are utilized by the peripheral tissues. /Amino acids/ NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 599, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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For more Absorption, Distribution and Excretion (Complete) data for (L)-Tryptophan (9 total), please visit the HSDB record page.

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10.6 Metabolism/Metabolites

Hepatic.

DrugBank

In Hartnup disease ... tryptophane appear/s/ in urine due to defective renal and intestinal absorption of tryptophane ... It is an intermediary metabolite in the synthesis of serotonin (5- hydroxytryptamine) and 5-hydroxyindole acetic acid (HIAA). Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 590

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Patients with bladder cancer excreted significantly more kynurenic acid, acetylkynurenine, kynurenine, and 3-hydroxykynurenine after ingesting a loading dose of L-tryptophan than did control subjects with no known disease. Searle, C. E. (ed.). Chemical Carcinogens. ACS Monograph 173. Washington, DC: American Chemical Society, 1976., p. 443

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Tryptophan is metabolized in the liver by tryptophan pyrrolase and tryptophan hydroxylase. Metabolites include hydroxytryptophan, which is then converted to serotonin, and kynurenine derivatives. Some tryptophan is converted to nicotinic acid and nicotinamide. Pyridoxine and ascorbic acid are cofactors in the decarboxylation and hydroxylation, respectively, of tryptophan; pyridoxine apparently prevents the accumulation of the kynurenine metabolites. Sweetman SC (ed), Martindale: The Complete Drug Reference. London: Pharmaceutical Press (2009), p.427.

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Yields indole-3-pyruvic acid in man ... and in rats; yields tryptamine in guinea pigs. /From table/ Goodwin, B.L. Handbook of Intermediary Metabolism of Aromatic Compounds. New York: Wiley, 1976., p. T-38

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Yields 5-hydroxy-l-tryptophan in rabbits, guinea pigs, and rats ... and in mice; yields indole-3-acrylic acid in man. /From table/ Goodwin, B.L. Handbook of Intermediary Metabolism of Aromatic Compounds. New York: Wiley, 1976., p. T-37

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Yields n-formyl-L-kynurenine in rats, ... man, ... rabbits ...and guinea pigs. /From table/ Goodwin, B.L. Handbook of Intermediary Metabolism of Aromatic Compounds. New York: Wiley, 1976., p. T-37

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Yields n-acetyl-l-tryptophan in man ... and rats. /From table/ Goodwin, B.L. Handbook of Intermediary Metabolism of Aromatic Compounds. New York: Wiley, 1976., p. T-37

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... Those metabolites of tryptophan which lie on the niacin pathway were o-aminophenol derivatives and, as o-aminophenols, were postulated to be active metabolites of aromatic amines ... Searle, C. E. (ed.). Chemical Carcinogens. ACS Monograph 173. Washington, DC: American Chemical Society, 1976., p. 442

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Recent studies have suggested that carbon disulfide exposure can induce kynureninase and lead to disorders of tryptophan metabolism. Amdur, M.O., J. Doull, C.D. Klaasen (eds). Casarett and Doull's Toxicology. 4th ed. New York, NY: Pergamon Press, 1991., p. 711

Hazardous Substances Data Bank (HSDB) https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 31/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

/This/ work is an up-to-date approach to study the correlation between the excretion pattern of tryptophan metabolites along the kynurenine pathway (after loading with 2 g L-tryptophan), and the N-nitrosamine content in urine of bilharzial bladder cancer patients. The control group was composed of healthy subjects who had no reported history of Schistosoma haematobium infection and no current bacterial cystitis. The N-nitrosamine content was determined by the colorimetric method of Eisebrand and Preussmann (1970). It was demonstrated that 64% of the patients metabolized the tryptophan load abnormally and the others metabolized it almost normally. Moreover, the N-nitrosamines were present in 43% in 43% of controls and 93% of patients have these derivatives in higher values. The presence of an inverse correlation between certain tryptophan metabolites, shown previously to be bladder carcinogens, and the N- nitrosamine content, especially after loading,was interpreted in view of the possible conversion of some tryptophan metabolites into N-nitrosamines either under endovesical conditions or during the execution of the colorimetric determination of these compounds. PMID:3083120 Abdel-Tawab GA et al; J Urol 135 (4): 826-30 (1986).

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... /The authors/ investigated the effects of pregnancy on the metabolism of tryptophan to niacin in rats. The daily urine samples were collected from day -17 and day +6 (the delivery day was designated as day 0) and the intermediates of tryptophan to niacin were measured. The metabolites such as kynurenic acid, xanthurenic acid, anthranilic acid, 3-hydroxyanthranilic acid, quinolinic acid, N1-methylnicotinamide, N1-methyl-2-pyridone-5-carboxamide, N1-methyl-4-pyridone-3-carboxamide were increased with progress in pregnant and returned to normal levels after the delivery. The catabolism of tryptophan is accelerated during pregnancy. PMID:15206761 Shibata K et al; Adv Exp Med Biol 527: 435-41 (2003).

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Once the amino acid deamination products enter the tricarboxylic acid (TCA) cycle (also known as the citric acid cycle or Krebs cycle) or the glycolytic pathway, their carbon skeletons are also available for use in biosynthetic pathways, particularly for glucose and fat. Whether glucose or fat is formed from the carbon skeleton of an amino acid depends on its point of entry into these two pathways. If they enter as acetyl-CoA, then only fat or ketone bodies can be formed. The carbon skeletons of other amino acids can, however, enter the pathways in such a way that their carbons can be used for gluconeogenesis. This is the basis for the classical nutritional description of amino acids as either ketogenic or glucogenic (ie, able to give rise to either ketones [or fat] or glucose). Some amino acids produce both products upon degradation and so are considered both ketogenic and glucogenic. /Amino acids/ NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 606, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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The effects of excess nicotinic acid administration on body weight gain, food intake, and urinary excretion of water-soluble vitamins and the metabolism of tryptophan /were investigated/ in weaning rats. The weaning rats were freely fed a niacin-free 20% casein diet (control diet) or the same diet with 0.1%, 0.3% or 0.5% nicotinic acid for 23 days. The excess nicotinic acid intake did not affect body weight gain, food intake, serotonin contents in the brain, stomach and small intestine, or the urinary excretions of water-soluble vitamins. Although excess nicotinic acid did not affect the upper part of the tryptophan-nicotinamide pathway, 0.5% nicotinic acid diet increased the urinary excretion of quinolinic acid... Fukuwatari T et al; Shokuhin Eiseigaku Zasshi 50 (2): 80-4 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19436156

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... Convenience samples of 235 cats submitted for diagnostic feline immunodeficiency virus (FIV) FIV serology (115 FIV-negative and 120 FIV-positive cats) /were collect and/ serum was assayed for tryptophan and kynurenine ... . Tryptophan and kynurenine concentrations were log-normally distributed. Geometric mean concentrations were: tryptophan: FIV-positive 30.6 uM (95% CI: 26.8 34.8 uM), FIV-negative 48.9 [uM (95% CI: 43.6-54.9 uM) (P < .001); kynurenine: FIV-positive 22.7 uM (95% CI: 25.5-10.9 uM), FIV-negative 9.9 uM (95% CI: 20.3-9.03 uM) (P < .001). The ratio of kynurenine to tryptophan was: FIV-positive 4.93 (95% CI: 5.62-4.32), FIV-negative 1.34 (95% CI: 1.53 1.17) (P < .0001). ... Serum tryptophan concentration was significantly lower and serum kynurenine concentration was significantly higher in FIV-positive cats. The kynurenine: tryptophan ratio was >3-fold higher in FIV-positive animals, indicating increased tryptophan catabolism in this group. Dietary or pharmacologic intervention to support serum tryptophan concentrations has been shown to be clinically useful in humans with AIDS and might be applicable to cats with FIV infection. Kenny MJ et al; J Vet Intern Med 21 (3): 539-41 (2007). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=17552465

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Abnormal tryptophan metabolism catalyzed by indoleamine 2,3-dioxygenase may play a prominent role in tumor immunoresistance in many tumor types, including lung tumors. The goal of this study was to evaluate the in vivo kinetics of alpha-(11)C-methyl-l-tryptophan (AMT), a PET tracer for tryptophan metabolism, in human lung tumors. Tracer transport and metabolic rates were evaluated in 18 lesions of 10 patients using dynamic PET/CT with AMT. The kinetic values were compared between tumors and unaffected lung tissue, tested against a simplified analytic approach requiring no arterial blood sampling, and correlated with standardized uptake values (SUVs) obtained from (18)F-FDG PET/CT scans. ... Most non-small cell lung cancers (NSCLCs) showed prolonged retention of AMT, but 3 other lesions (2 benign lesions and a rectal cancer metastasis) and unaffected lung tissue showed no such retention. Transport and metabolic rates of AMT were substantially higher in NSCLCs than in the other tumors and unaffected lung tissue. A simplified analytic approach provided an excellent estimate of transport rates but only suboptimal approximation of tryptophan metabolic rates. (18)F-FDG SUVs showed a positive correlation with AMT uptake, suggesting higher tryptophan transport and metabolism in tumors with higher proliferation rates... Juhasz C et al; J Nucl Med 50 (3): 356-63 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19223408

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Some people may take excessive tryptophan as a supplement in the expectation that the tryptophan metabolite, melatonin, will help to induce sufficient sleep. ... TYhe basis for a useful index to assess the risk of a tryptophan excess. Young rats were fed on a 20% casein diet with 0, 0.5, 1.0, 2.0 or 5.0% added tryptophan for 30 d the apparent toxicity and growth retardation was observed in the 5.0% tryptophan-added group. Metabolites of the Tryptophan-nicotinamide pathway and such intermediates as kynurenic acid (KA), anthranilic acid (AnA), xanthurenic acid, 3-hydroxyanthranilic acid and quinolinic acid in 24-hr urine increased in a dose-dependent manner. Of those metabolites and intermediates, the urinary excretion of KA progressively increased, and that of AnA dramatically increased in the 2.0 and 5.0% tryptophan-added groups. The urinary excretory ratio of AnA/KA was a high value for both the groups. These results suggest that the urinary ratio of AnA/KA could be a useful index to monitor an excessive tryptophan intake. Okuno A et al; Biosci Biotech Biochem 72 (7): 1667-72 (2008). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=18603814

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Major depressive disorder (MDD) and suicide are associated with deficient serotonergic neurotransmission. Tryptophan hydroxylase (TPH) is the rate-limiting biosynthetic enzyme for serotonin. ... Elevated levels of TPH protein in the dorsal raphe nucleus (DRN) of depressed suicides /were previously reported/ and now the expression of neuronal TPH2 mRNA /is examined/ in a cohort of matched controls and suicides (n = 11 pairs). DRN TPH2 mRNA was measured by densitometric analysis of autoradiograms from in situ hybridization histochemistry experiments. TPH2 mRNA is confirmed as the raphe-specific isoform of TPH in human brain, and is expressed in neurons throughout the anteroposterior extent of the DRN and median raphe nucleus (MRN). TPH2 mRNA expression correlates with TPH protein distribution in the DRN, and has a negative correlation with age. In drug-free suicides, TPH2 expression is 33% higher in the DRN and 17% higher in the MRN as compared to matched nonpsychiatric controls. Higher levels of TPH2 mRNA were found throughout the entire extent of the rostrocaudal axis of the DRN, and were not specific to any single subnucleus. Higher TPH2 mRNA expression may explain more TPH protein observed in depressed suicides and reflect a homeostatic response to deficient brain serotonergic transmission. /Tryptophan hydroxylase/ https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 32/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Bach-Mizrachi H et al; Neuropsychopharmacol 31 (4): 814-24 (2006). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi? cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16192985

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It was recently reported that a rare functional variant, R441H, in the human tryptophan hydroxylase-2 gene (hTPH2) could represent an important risk factor for unipolar major depression (UP) since it was originally found in 10% of UP patients (vs. 1.4% in control subjects). /The authors/ explored the occurrence of this variation in patients with affective disorders (n = 646), autism spectrum disorders (n = 224), and obsessive-compulsive disorder (OCD) (n = 201); in healthy volunteers with no psychiatric disorders (n = 246); and in an ethnic panel of control individuals from North Africa, Sub-Saharan Africa, India, China, and Sweden (n = 277). RESULTS: Surprisingly, ... the R441H variant /was not observed/ in any of the individuals screened (3188 independent chromosomes). /These/ results do not confirm the role of the R441H mutation of the hTPH2 gene in the susceptibility to UP... /Tryptophan hydroxylase-2/. The absence of the variant from a large cohort of psychiatric patients and control subjects suggests that the findings reported in the original study could be due to a genotyping error or to stratification of the initial population reported. Additional data by other groups should contribute to the clarification of the discrepancy between our results and those previous published. /Tryptophan hydroxylase-2/ Delorme R et al; Biol Psychiatry 60 (2): 202-3 (2006). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16581035

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... Several polymorphisms in the gene coding for the brain-specific tryptophan hydroxylase (TPH2) have been associated with susceptibility to psychiatric diseases. ... This study ... analyzed the correlation between TPH2 polymorphisms and response to antidepressant drugs. The study included 182 patients who received drug treatment for major depression. To assess the variability in the TPH2 gene, four single nucleotide polymorphisms (SNPs) tagging the common TPH2 haplotypes and six SNPs medically relevant according to data from other studies were analyzed in a multiplex single base primer extension reaction. Two SNPs, rs10897346 and rs1487278, were significantly associated with response to therapy (P=0.003 and 0.007). The rs10897346 variant showed the highest predictive values with carriers of null C alleles showing a 2.6-fold increased risk (95% confidence interval 1.4-4.8) for nonresponse compared with the others. The effect was found in all major types of antidepressant medications administered in this study and was statistically significant in the subgroup on selective serotonin reuptake inhibitors. Multiple logistic regression analyses confirmed the rs10879346 polymorphism as an independent predictor of the antidepressant response (odds ratio: 3.86; 1.75-8.55, P=0.0008). The therapeutically relevant variant rs10897346 is completely linked with the functional Pro312Pro polymorphism, which is known to affect TPH2 expression and may influence serotonin synthesis in the brain. /It was concluded that/ the polymorphisms rs10897346 and Pro312Pro in the TPH2 gene might play an important role for TPH2 expression and antidepressant drug response. /Tryptophan hydrolase/ Tzvetkov MV et al; Pharmacogenetics Genomics 18 (6): 495-506 (2008). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi? cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=18496129

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Bipolar affective disorder (BPAD) is a highly inherited genetic disorder and may be caused in part by deficits in serotonergic neurotransmission. ...Whether variants within the tryptophan hydroxylase-2 (TPH2) gene, which is required for the synthesis of serotonin (5-HT), are associated with susceptibility to developing BPAD /was investigated/. Thirteen single nucleotide polymorphisms (SNPs) within TPH2 were genotyped in a collection of 151 Irish BPAD type I trios and were tested for association using the transmission disequilibrium test. SNPs rs1386482 and rs1386486, which are in very strong linkage disequilibrium, were associated with BPAD (P=0.006). The association retained significance after a correction for multiple testing. The associated SNPs are in perfect linkage disequilibrium with SNPs previously associated with BPAD (rs4290270) and impulsivity (rs1386483), a core trait of BPAD. These results strongly support a role for TPH2 in the aetiology of BPAD. /Tryptophan hydroxylase-2/ Roche S, McKeon P; Psychiatric Genetics 19 (3): 142-6 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19352219

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Dysfunction of the central serotonergic system has been related to a spectrum of psychiatric disorders, including suicidal behavior. Tryptophan hydroxylase isoform 2 (TPH2) is the rate-limiting enzyme in the biosynthetic pathway of serotonin, being expressed in serotonergic neurons of raphe nuclei. ...Genetic variation in TPH2 gene /was investigated/ in two samples of male subjects: 288 suicide completers and 327 volunteers, in order to reveal any associations between 14 single nucleotide polymorphisms and completed suicide. No associations were revealed neither on allelic nor haplotype level. /Tryptophan hydroxylase-2/ Must A et al; Neurosci Lett 453 (2): 112-4 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=19356604

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10.7 Biological Half-Life

The biological half-life of tryptophan was reported to be 15.8 hr. Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 61

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10.8 Mechanism of Action

A number of important side reactions occur during the catabolism of tryptophan on the pathway to acetoacetate. The first enzyme of the catabolic pathway is an iron porphyrin oxygenase that opens the indole ring. The latter enzyme is highly inducible, its concentration rising almost 10-fold on a diet high in tryptophan. Kynurenine is the first key branch point intermediate in the pathway. Kynurenine undergoes deamniation in a standard transamination reaction yielding kynurenic acid. Kynurenic acid and metabolites have been shown to act as antiexcitotoxics and anticonvulsives. A second side branch reaction produces anthranilic acid plus alanine. Another equivalent of alanine is produced further along the main catabolic pathway, and it is the production of these alanine residues that allows tryptophan to be classified among the glucogenic and ketogenic amino acids. The second important branch point converts kynurenine into 2- amino-3-carboxymuconic semialdehyde, which has two fates. The main flow of carbon elements from this intermediate is to glutarate. An important side reaction in liver is a transamination and several rearrangements to produce limited amounts of nicotinic acid, which leads to production of a small amount of NAD+ and NADP+.

DrugBank

Findings indicate that enhanced rates of serotonin turnover produced by (L)-tryptophan and physical restraint are associated with inhibition of thyroid-stimulating hormone (TSH) and stimulation of prolactin release from anterior pituitary in rats. PMID:1083471 Mueller GP et al; Life Sci 18 (7): 715-24 (1976)

Hazardous Substances Data Bank (HSDB)

L-Tryptophan, an indispensable amino acid, serves as a precursor for several small molecules of functional significance including the vitamin niacin, the neurotransmitter serotonin, the metabolite tryptamine, and the pineal hormone melatonin. Increases in tryptophan have been shown to increase synthesis of the neurotransmitters in brain, blood, and other body organs. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 731, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

Hazardous Substances Data Bank (HSDB) https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 33/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Amino acids are selected for protein synthesis by binding with transfer RNA (tRNA) in the cell cytoplasm. The information on the amino acid sequence of each individual protein is contained in the sequence of nucleotides in the messenger RNA (mRNA) molecules, which are synthesized in the nucleus from regions of DNA by the process of transcription. The mRNA molecules then interact with various tRNA molecules attached to specific amino acids in the cytoplasm to synthesize the specific protein by linking together individual amino acids; this process, known as translation, is regulated by amino acids (e.g., leucine), and hormones. Which specific proteins are expressed in any particular cell and the relative rates at which the different cellular proteins are synthesized, are determined by the relative abundances of the different mRNAs and the availability of specific tRNA-amino acid combinations, and hence by the rate of transcription and the stability of the messages. From a nutritional and metabolic point of view, it is important to recognize that protein synthesis is a continuing process that takes place in most cells of the body. In a steady state, when neither net growth nor protein loss is occurring, protein synthesis is balanced by an equal amount of protein degradation. The major consequence of inadequate protein intakes, or diets low or lacking in specific indispensable amino acids relative to other amino acids (often termed limiting amino acids), is a shift in this balance so that rates of synthesis of some body proteins decrease while protein degradation continues, thus providing an endogenous source of those amino acids most in need. /Amino acids/ NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 601-602, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

Hazardous Substances Data Bank (HSDB)

The mechanism of intracellular protein degradation, by which protein is hydrolyzed to free amino acids, is more complex and is not as well characterized at the mechanistic level as that of synthesis. A wide variety of different enzymes that are capable of splitting peptide bonds are present in cells. However, the bulk of cellular proteolysis seems to be shared between two multienzyme systems: the lysosomal and proteasomal systems. The lysosome is a membrane-enclosed vesicle inside the cell that contains a variety of proteolytic enzymes and operates mostly at acid pH. Volumes of the cytoplasm are engulfed (autophagy) and are then subjected to the action of the protease enzymes at high concentration. This system is thought to be relatively unselective in most cases, although it can also degrade specific intracellular proteins. The system is highly regulated by hormones such as insulin and glucocorticoids, and by amino acids. The second system is the ATP-dependent ubiquitin-proteasome system, which is present in the cytoplasm. The first step is to join molecules of ubiquitin, a basic 76-amino acid peptide, to lysine residues in the target protein. Several enzymes are involved in this process, which selectively targets proteins for degradation by a second component, the proteasome. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 602, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

Hazardous Substances Data Bank (HSDB)

Indoleamine 2,3-dioxygenase is an enzyme that catabolizes tryptophan to kynurenine. ... The consequences of IDO induction by IFN-gamma /was investigated/ in polarized human bronchial epithelium. IDO mRNA expression was undetectable in resting conditions, but strongly induced by IFN-gamma. ... The concentration of tryptophan and kynurenine /were measured/ in the extracellular medium, and ... apical tryptophan concentration was lower than the basolateral in resting cells. IFN-gamma caused a decrease in tryptophan concentration on both sides of the epithelium. Kynurenine was absent in control conditions, but increased in the basolateral medium after IFN-gamma treatment. The asymmetric distribution of tryptophan and kynurenine suggested the presence of a transepithelial amino acid transport. Uptake experiments with radiolabeled amino acids demonstrated the presence of a Na(+)-dependent amino acid transporter with broad specificity that was responsible for the tryptophan/kynurenine transport. ...These data /were confirmed/ by measuring the short-circuit currents elicited by direct application of tryptophan or kynurenine to the apical surface. The rate of amino acid transport was dependent on the transepithelial potential, and we established that in cystic fibrosis epithelia, in which the transepithelial potential is significantly more negative than in noncystic fibrosis epithelia, amino acid uptake was reduced. This work suggests that human airway epithelial cells maintain low apical tryptophan concentrations by two mechanisms, a removal through a Na(+)-dependent amino acid transporter and an IFN-gamma-inducible degradation by IDO. Zegarra-Moran O; Journal of immunology 173 (1): 542-9 (2004). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15210815

Hazardous Substances Data Bank (HSDB)

Myeloperoxidase (MPO) binds H2O2 in the absence and presence of chloride (Cl-) and catalyzes the formation of potent oxidants through 1e(-) and 2e(-) oxidation pathways. These potent oxidants have been implicated in the pathogenesis of various diseases including atherosclerosis, asthma, arthritis, and cancer. Thus, inhibition of MPO and its by-products may have a wide application in biological systems. Using direct rapid kinetic measurements and H2O2-selective electrodes, /it was shown that tryptophan (Trp), an essential amino acid, is linked kinetically to the inhibition of MPO catalysis under physiological conditions. Trp inactivated MPO in the absence and presence of plasma levels of Cl(-), to various degrees, through binding to MPO, forming the inactive complexes Trp-MPO and Trp-MPO-Cl, and accelerating formation of MPO Compound II, an inactive form of MPO. Inactivation of MPO was mirrored by the direct conversion of MPO-Fe(III) to MPO Compound II without any sign of Compound I accumulation. This behavior indicates that Trp binding modulates the formation of MPO intermediates and their decay rates. Importantly, Trp is a poor substrate for MPO Compound II and has no role in destabilizing complex formation. Thus, the overall MPO catalytic activity will be limited by: (1) the dissociation of Trp from Trp-MPO and Trp-MPO-Cl complexes, (2) the affinity of MPO Compound I toward Cl(-) versus Trp, and (3) the slow conversion of MPO Compound II to MPO-Fe(III). Importantly, Trp- dependent inhibition of MPO occurred at a wide range of concentrations that span various physiological and supplemental ranges. Galijasevic S et al; Free Rad Biol Med 44 (8): 1570-7 (2008). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=18279680

Hazardous Substances Data Bank (HSDB)

In human subjects, the acute tryptophan (TRP) depletion (ATD) paradigm has been shown to have effects on mood and cognition. It is assumed that these effects are mediated through the serotonin system. In this study, we have examined the effects of ATD on the central concentrations of the monoamine transmitters, noradrenaline (NA) and dopamine (DA) as well as on serotonin (5-HT). Effects on NA and DA could also affect mood and cognition. Following oral administration of TRP-containing (TRP+) and TRP-free (TRP-) amino acid mixtures, neurotransmitter concentrations and free plasma TRP concentrations were determined by High Performance Liquid Chromatography (HPLC) with electrochemical detection. Free plasma TRP was significantly and substantially reduced (79%) in rats given a TRP- amino acid mixture when compared with those given a TRP+ mixture. ATD also significantly decreased 5-HT and 5- hydroxyindolacetic acid in the frontal cortex, remaining cortex and hippocampus, but did not significantly reduce these in the striatum. Furthermore, ATD did not significantly alter the concentration of NA and DA in any brain region examined. This study demonstrates that the administration of a TRP- amino acid mixture in rats can reduce free plasma TRP to levels comparable to those reported in human studies. These results indicate that behavioral and cognitive changes produced by ATD in preclinical or clinical studies are likely to be due to specific effects on the serotonergic system. Ardis TC et al; J Psychopharm 23 (1): 51-5 (2009). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=18562433

Hazardous Substances Data Bank (HSDB)

10.9 Human Metabolite Information

10.9.1 Tissue Locations

Fibroblasts Neuron Placenta Prostate

Human Metabolome Database (HMDB)

10.9.2 Cellular Locations https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 34/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Extracellular

Human Metabolome Database (HMDB)

10.9.3 Metabolite Pathways

Transcription/Translation Tryptophan Metabolism

Human Metabolome Database (HMDB)

10.10 Biochemical Reactions

PubChem

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 35/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

11 Use and Manufacturing

11.1 Use Classification

Human drugs -> Rare disease (orphan)

European Medicines Agency (EMA)

Human Drugs -> EU pediatric investigation plans

European Medicines Agency (EMA)

Cosmetics -> Antistatic S13 | EUCOSMETICS | Combined Inventory of Ingredients Employed in Cosmetic Products (2000) and Revised Inventory (2006) | DOI:10.5281/zenodo.2624118

NORMAN Suspect List Exchange

11.2 Uses

EPA CPDat Chemical and Product Categories

14 items View More

SORT BY Category

Category Category Description Categorization Type

Drug Drug product, or related to the manufacturing of drugs; modified by veterinary, animal, or pet if indicated by source CPCat Cassette

Drug, antidepressant Pharmaceutical related CPCat Cassette

Drug, dietary_supplement Pharmaceutical related CPCat Cassette

Drug, discontinued Pharmaceutical related CPCat Cassette

Drug, essential_amino_acid Pharmaceutical related CPCat Cassette

1 2 3 Next

EPA Chemical and Products Database (CPDat)

Nutrition and research; medicine; dietary supplement; cereal enrichment /Tryptophan/ Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 1292

Hazardous Substances Data Bank (HSDB)

Probe for studying protein structure and dynamics O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1683

Hazardous Substances Data Bank (HSDB)

Nutritional supplement (amino acid) in drugs and foods SRI

Hazardous Substances Data Bank (HSDB)

BIOLOGICAL ACTIVITIES: Analgesic; Antidementia; Antidepressant; Antidyskinetic; Antihypertensive; Antiinsomniac; Antimanic; Antimenopausal; Antimigraine; Antioxidant; Antiparkinsonian; Antiphenylketonuric; Antiprostaglandin; Antipsychotic; Antirheumatic; Antiscolioticn;;Carcinogenic; Essential; Hypnotic; Hypoglycemic; Hypotensive; Insulinase-Inhibitor; Insulinotonic;Monoamine-Precursor; Prolactinogenic; Sedative; Serotoninergic; Tumor-Promoter /Tryptophan/ Dr. Duke's Phytochemical and Ethnobotanical Databases. Plants with a chosen chemical. Tryptophan. Washington, DC: US Dept Agric, Agric Res Service. Available from, as of August 13, 2010: http://www.ars- grin.gov/duke/

Hazardous Substances Data Bank (HSDB)

THERAPEUTIC CATEGORY: In treatment of depression, schizophrenia and other neuropsychiatric disorders O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 2006., p. 1682

Hazardous Substances Data Bank (HSDB)

Medication

Hazardous Substances Data Bank (HSDB)

11.3 Methods of Manufacturing

Fermentation of natural or biologically available substances with Corynebacterium glutamicum; enzymatically from indole, pyruvic acid, and ammonia using microbial tryptophanase SRI

Hazardous Substances Data Bank (HSDB)

Synthesis starting with beta-indolylaldehyde and hippuric acid; ... from hydantoin; alternate route starting with 3-indoleacetonitrile. Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989., p. 1540 https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 36/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Hazardous Substances Data Bank (HSDB)

11.4 Formulations/Preparations

Grades: Reagent; Technical; Food Chemicals Codex /Tryptophan/ Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 1292

Hazardous Substances Data Bank (HSDB)

(L)-Tryptophan with plant oils in soft gelatin capsules. Klosa J; Ger Offen Patent No 2824362 12/13/79

Hazardous Substances Data Bank (HSDB)

Source: Hazardous Substances Data Bank (HSDB) Record Name: (L)-Tryptophan URL: https://pubchem.ncbi.nlm.nih.gov/source/hsdb/4142 Description: The Hazardous Substances Data Bank (HSDB) is a toxicology database that focuses on the toxicology of potentially hazardous chemicals. It provides information on human exposure, industrial hygiene, emergency handling procedures, environmental fate, regulatory requirements, nanomaterials, and related areas. The information in HSDB has been assessed by a Scientific Review Panel.

11.5 U.S. Production

(1977) Not produced commercially in USA SRI

Hazardous Substances Data Bank (HSDB)

(1979) Not produced commercially in USA SRI

Hazardous Substances Data Bank (HSDB)

Production volumes for non-confidential chemicals reported under the Inventory Update Rule.

Year Production Range (pounds)

1986 10 thousand - 500 thousand

1990 No Reports

1994 No Reports

1998 No Reports

2002 No Reports

US EPA; Non-confidential Production Volume Information Submitted by Companies for Chemicals Under the 1986-2002 Inventory Update Rule (IUR). L-Tryptophan (73-22-3). Available from, as of March 23, 2010: http://www.epa.gov/oppt/iur/tools/data/2002-vol.html

Hazardous Substances Data Bank (HSDB)

11.6 U.S. Imports

(1977) 2.34 X 10+7 g (Princpl Custms Dists) SRI

Hazardous Substances Data Bank (HSDB)

(1979) 2.47 X 10+7 g (Princpl Custms Dists) SRI

Hazardous Substances Data Bank (HSDB)

11.7 General Manufacturing Information

EPA TSCA Commercial Activity Status

L-Tryptophan: ACTIVE https://www.epa.gov/tsca-inventory

EPA Chemicals under the TSCA

Hazardous Substances Data Bank (HSDB)

60 mg of tryptophan is approx equiv to 1.0 mg of niacin. /Tryptophan/ Furia, T.E. (ed.). CRC Handbook of Food Additives. 2nd ed. Cleveland: The Chemical Rubber Co., 1972., p. 89

Hazardous Substances Data Bank (HSDB)

The amino acids that are incorporated into mammalian protein are alpha-amino acids, with the exception of proline, which is an alpha-imino acid. This means that they have a carboxyl group, an amino nitrogen group, and a side chain attached to a central alpha-carbon. Functional differences among the amino acids lie in the structure of their side chains. In addition to differences https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 37/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

in size, these side groups carry different charges at physiological pH (e.g., nonpolar, uncharged but polar, negatively charged, positively charged); some groups are hydrophobic (e.g., branched chain and aromatic amino acids) and some hydrophilic (most others). These side chains have an important bearing on the ways in which the higher orders of protein structure are stabilized and are intimate parts of many other aspects of protein function. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 592, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

Hazardous Substances Data Bank (HSDB)

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 38/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

12 Identification

12.1 Analytic Laboratory Methods

Method: AOAC 960.47; Procedure: microbiological, turbidimetric and titrimetric methods; Analyte: tryptophan; Matrix: vitamin preparations; Detection Limit: not provided. Official Methods of Analysis of AOAC International, 18th Edition Online. Tryptophan (73-22-3). Available from, as of March 25, 2010: http://www.aoac.org

Hazardous Substances Data Bank (HSDB)

Method: AOAC 988.15; Procedure: ion exchange chromatographic method; Analyte: tryptophan; Matrix: foods and food & feed ingredients; Detection Limit: not provided. Official Methods of Analysis of AOAC International, 18th Edition Online. Tryptophan (73-22-3). Available from, as of March 25, 2010: http://www.aoac.org

Hazardous Substances Data Bank (HSDB)

TECHNIQUE OF DOUBLE-BEAM FLUORESCENCE SPECTROPHOTOMETRY FOR DETERMINATION OF TRYPTOPHAN IN PROTEINS. PORRO TJ, TERHAAR DA; ANAL CHEM 48 (13): 1103 (1976)

Hazardous Substances Data Bank (HSDB)

Determination of tryptophan in foods by isocratic reversed-phase HPLC. Hagen SR, Augustin J; J Micronutr Anal 5 (4): 303-9 (1989)

Hazardous Substances Data Bank (HSDB)

12.2 Clinical Laboratory Methods

The plasma levels of 5-HT and its metabolites were determined by a HPLC system coupled with an amperometric detector. The HPLC system uses a reversed-phase column IRICA RP-18, with 4-hydroxyphenylacetic acid as internal std. The detection sensitivity of the HPLC system for 5-HTP, 5-HT, tryptophan, and 5-HIAA was 6.0, 7.1, 17.5, and 7.6 pg, resptively, with recovery rates of apprx 99% and intrassay relative standard deviations of <5% Okatani Y, Sagara Y; Sanfujinka Chiryo 56 (2): 230 (1988)

Hazardous Substances Data Bank (HSDB)

An HPLC method for the determination of tryptophan and its metabolites in maternal and umbilical cord plasma is described. Chromatography was carried out on a column packed with 10 um IRICA RP-18 using as mobile phase a mixture of 0.1 M NaOAc, 0.1 M citric acid, 0.03 mM Na2EDTA, and 5-30% acetonitrile or 10-37% MeOH. Recovery range was99.0-100.7% for tryptophan and its metabolites. Interassay relative standard deviation was in the range of 1.5-5.7% for tryptophan and its metabolites. Detection limits were <150 pg/ml for 5-HTP, 177.5 pg/ml for 5-HT): 190 pg/ml for 5-HIAA, 437 pg/ml for tryptophan. The detection limits for 5-HT and 5-HIAA were sufficient for clinical determination of pregnancy. The method was applied to the determination of tryptophan and metabolites in maternal vein plasma and in umbilical artery and vein plasma. PMID:2466859 Sagara Y et al; J Chromatogr 431 (1): 170-6 (1988)

Hazardous Substances Data Bank (HSDB)

A capillary electrophoresis method for separation and detection with time-of-flight mass spectrometry is described for tryptophan metabolites in the kynurenic pathway... Arvidsson B et al; J Chromatog A 1159 (1-22): 154-8 (2007). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=17477928

Hazardous Substances Data Bank (HSDB)

A liquid chromatographic-tandem mass spectrometric method measures 3-hydroxykynurenine and 3-hydroxyanthranilic acid in addition to tryptophan and kynurenine both intra- and extracellularly. After reversed phase HPLC separation, the compounds were detected in the MS positive multiple reaction monitoring mode... Yamada K et al; J Chromatog B 867 (1): 57-61 (2008). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=18395499

Hazardous Substances Data Bank (HSDB)

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 39/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

13 Safety and Hazards

13.1 Hazards Identification

13.1.1 GHS Classification

Not Classified GHS Hazard Statements Reported as not meeting GHS hazard criteria by 85 of 87 companies (only ~ 2.3% companies provided GHS information). For more detailed information, please visit ECHA C&L website.

European Chemicals Agency (ECHA)

13.1.2 Health Hazards

ACUTE/CHRONIC HAZARDS: When heated to decomposition this compound emits toxic fumes. (NTP, 1992) National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

CAMEO Chemicals

13.1.3 Fire Hazards

Flash point data for this chemical are not available. It is probably combustible. (NTP, 1992) National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

CAMEO Chemicals

13.2 First Aid Measures

13.2.1 First Aid

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment. INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing. INGESTION: DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital. (NTP, 1992) National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

CAMEO Chemicals

13.3 Fire Fighting

Fires involving this material should be controlled using a dry chemical, carbon dioxide or Halon extinguisher. (NTP, 1992) National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

CAMEO Chemicals

13.4 Accidental Release Measures

13.4.1 Disposal Methods

SRP: Criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Hazardous Substances Data Bank (HSDB)

SRP: At the time of review, regulatory criteria for small quantity disposal are subject to significant revision, however, household quantities of waste pharmaceuticals may be managed as follows: Mix with wet cat litter or coffee grounds, double bag in plastic, discard in trash.

Hazardous Substances Data Bank (HSDB)

SRP: Expired or waste pharmaceuticals shall carefully take into consideration applicable DEA, EPA, and FDA regulations. It is not appropriate to dispose by flushing the pharmaceutical down the toilet or discarding to trash. If possible return the pharmaceutical to the manufacturer for proper disposal being careful to properly label and securely package the material. Alternatively, the waste pharmaceutical shall be labeled, securely packaged and transported by a state licensed medical waste contractor to dispose by burial in a licensed hazardous or toxic waste landfill or incinerator.

Hazardous Substances Data Bank (HSDB)

13.5 Handling and Storage https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 40/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

13.5.1 Nonfire Spill Response

SMALL SPILLS AND LEAKAGE: If you spill this chemical, you should dampen the solid spill material with water, then transfer the dampened material to a suitable container. Use absorbent paper dampened with water to pick up any remaining material. Seal your contaminated clothing and the absorbent paper in a vapor-tight plastic bag for eventual disposal. Wash all contaminated surfaces with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned. STORAGE PRECAUTIONS: You should keep this material in a tightly-closed container under an inert atmosphere, and store it in a refrigerator. (NTP, 1992) National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

CAMEO Chemicals

13.5.2 Storage Conditions

Protect from light Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 61

Hazardous Substances Data Bank (HSDB)

13.6 Exposure Control and Personal Protection

13.6.1 Allowable Tolerances

Residues of tryptophan are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops only. Use: synergist. Limit: maximum of 5% of formulation. 40 CFR 180.920 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of March 22, 2010: http://www.ecfr.gov

Hazardous Substances Data Bank (HSDB)

13.6.2 Personal Protective Equipment (PPE)

RECOMMENDED RESPIRATOR: Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with an organic vapor/acid gas cartridge (specific for organic vapors, HCl, acid gas and SO2) with a dust/mist filter. (NTP, 1992) National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

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13.7 Stability and Reactivity

13.7.1 Air and Water Reactions

Slightly soluble in water.

CAMEO Chemicals

13.7.2 Reactive Group

Salts, Acidic

CAMEO Chemicals

13.7.3 Reactivity Profile

Acidic salts, such as L-TRYPTOPHAN, are generally soluble in water. The resulting solutions contain moderate concentrations of hydrogen ions and have pH's of less than 7.0. They react as acids to neutralize bases. These neutralizations generate heat, but less or far less than is generated by neutralization of inorganic acids, inorganic oxoacids, and carboxylic acid. They usually do not react as either oxidizing agents or reducing agents but such behavior is not impossible. Many of these compounds catalyze organic reactions.

CAMEO Chemicals

13.8 Regulatory Information

13.8.1 FIFRA Requirements

Residues of tryptophan are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops only. Use: synergist. Limit: maximum of 0.5% of formulation. 40 CFR 180.920 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of March 22, 2010: http://www.ecfr.gov

Hazardous Substances Data Bank (HSDB)

13.8.2 FDA Requirements

L-Tryptophan is a food additive permitted for direct addition to food for human consumption, as long as 1) the quantity of the substance added to food does not exceed the amount reasonably required to accomplish its intended physical, nutritive, or other technical effect in food, and 2) any substance intended for use in or on food is of appropriate food grade and is prepared and handled as a food ingredient. 21 CFR 172.320 (USFDA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of March 19, 2010: http://www.ecfr.gov https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 41/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Hazardous Substances Data Bank (HSDB)

Drug products containing certain active ingredients offered over-the-counter (OTC) for certain uses. A number of active ingredients have been present in OTC drug products for various uses, as described below. However, based on evidence currently available, there are inadequate data to establish general recognition of the safety and effectiveness of these ingredients for the specified uses: tryptophan is included in weight control drug products. 21 CFR 310.545(a)(20) (USFDA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of March 22, 2010: http://www.ecfr.gov

Hazardous Substances Data Bank (HSDB)

13.9 Other Safety Information

13.9.1 History and Incidents

In late 1989 the first notification linking the eosinophilia-myalgia syndrome with the use of tryptophan-containing products was made in the USA. There followed a number of similar published case reports from the USA, Europe, and Japan. Reviews of tryptophan-associated eosinophilia-myalgia syndrome have noted that by early 1990 over 1500 cases were known in the USA. In early 1990 the CDC in the USA summarized the features and known reports concerning the syndrome. As the name implies the characteristic features are an intense eosinophilia together with disabling fatigue and muscle pain, although multisystem organ involvement and inflammatory disorders affecting the joints, skin, connective tissue, lungs, heart, and liver have also been recorded. Symptoms have generally developed over several weeks and the syndrome has occurred in patients who had been receiving tryptophan for many years previously with no untoward effect. In most patients slow and gradual improvement in the degree of eosinophilia and other clinical manifestations has followed the withdrawal of tryptophan, but in some patients the disease has progressed despite withdrawal and there have been fatalities. The inflammatory condition has necessitated the use of corticosteroids in some patients. The eosinophilia-myalgia syndrome has been reported in patients taking both tryptophan-containing prescription products for depression and non-prescription dietary supplements for a number of disorders including insomnia, the premenstrual syndrome, and stress; it does not appear to have occurred in patients receiving amino-acid preparations containing tryptophan as part of total parenteral nutrition regimens. The recognition of this syndrome led to the withdrawal of tryptophan-containing products or severe restrictions being imposed upon their use in many countries during 1990. Various theories were proposed as to the reason for the association of tryptophan with this syndrome. Confusion existed because the reports implicated a very wide range of products from different manufacturers. However, later evidence appeared to have confirmed that contaminated tryptophan had originated from a single manufacturer in Japan. Bulk tryptophan was imported from Japan for manufacture into finished pharmaceutical dosage forms and it was noted in one of these reports that a single product was often found to contain two or more lots of powdered tryptophan that were blended together during the production of tablets or capsules. Many trace contaminants have been found in batches of tryptophan associated with the syndrome. One contaminant has been identified as 1,1'-ethylidenebis(tryptophan). Its inclusion in bulk tryptophan powder appeared to coincide with alterations in the manufacturing conditions that involved a change in the strain of Bacillus amyloliquefaciens used in the fermentation process and a reduction in the amount of charcoal used for purification. Other investigations indicated the presence of bacitracin-like peptides in batches of the contaminated tryptophan. However, further work has provided only weak support for an association between the syndrome and any one particular contaminant and the causative agent remains to be confirmed. Nonetheless, since the syndrome only appeared to be associated with tryptophan from one manufacturer, tryptophan preparations were reintroduced in the UK in 1994 for restricted use under carefully monitored conditions. In January 2005, the UK requirement for patient registration and monitoring was removed.[Sweetman SC (ed), Martindale: The Complete Drug Reference. online] London: Pharmaceutical Press. Available from, as of January 19, 2010: http://www.medicinescomplete.com/

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13.9.2 Special Reports

NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C. (2009).[Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html]

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DHEW/NCI; Bioassay of L-Tryptophan for Possible Carcinogenicity CAS No. 73-22-3 (NCI-CG-TR-71) (1978) Technical Report Series No. 71 DHEW Pub No. (NIH) 78-1321[Available from, as of March 29, 2010: http://ntp.niehs.nih.gov/ntp/htdocs/LT_rpts/tr071.pdf]

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https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 42/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

14 Toxicity

14.1 Toxicological Information

14.1.1 Acute Effects

14 items View More

Organism Test Type Route Dose Effect Reference

10960 mg/kg/20 BEHAVIORAL: MUSCLE WEAKNESS; LUNGS, THORAX, OR RESPIRATION: CHRONIC PULMONARY EDEMA; BLOOD: British Medical Journal., 301(21), women TDLo oral (10960 mg/kg) EOSINOPHILIA 1990 [PMID:2383703]

2700 LUNGS, THORAX, OR RESPIRATION: STRUCTURAL OR FUNCTIONAL CHANGE IN TRACHEA OR BRONCHI; LUNGS, Annals of Internal Medicine., women TDLo oral mg/kg/13W THORAX, OR RESPIRATION: ACUTE PULMONARY EDEMA; BLOOD: EOSINOPHILIA 112(301), 1990 [PMID:2297208] (2700 mg/kg)

3276 mg/kg/9W- BEHAVIORAL: MUSCLE WEAKNESS; BLOOD: EOSINOPHILIA; SKIN AND APPENDAGES (SKIN): DERMATITIS, Annals of Internal Medicine., women TDLo oral (3276 mg/kg) OTHER: AFTER SYSTEMIC EXPOSURE 112(344), 1990 [PMID:2306063]

9 gm/kg/22W-I Annals of Internal Medicine., women TDLo oral BEHAVIORAL: MUSCLE WEAKNESS; LIVER: LIVER FUNCTION TESTS IMPAIRED; BLOOD: EOSINOPHILIA (9000 mg/kg) 112(957), 1990 [PMID:2339856]

300 mg/kg (300 British Medical Journal., 2(701), man TDLo oral BEHAVIORAL: EXCITEMENT; BEHAVIORAL: ANTIANXIETY mg/kg) 1976

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ChemIDplus

14.1.2 Interactions

Acetylsalicylic acid reduced serum-protein binding of tryptophan in man, causing rise in free serum tryptophan. Changes in metabolic pattern also occurred, with increased urinary excretion of xanthurenic acid and 3-hydroxylkynurenine and decreased excretion of 3-hydroxyanthranilic acid. Searle, C. E. (ed.). Chemical Carcinogens. ACS Monograph 173. Washington, DC: American Chemical Society, 1976., p. 441

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Although tryptophan has been given to patients receiving MAOIs in the belief that clinical efficacy may be improved, it should be noted that the adverse effects may also be potentiated. Sweetman SC (ed), Martindale: The Complete Drug Reference. London: Pharmaceutical Press (2009), p.427.

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Use of tryptophan with drugs that inhibit the reuptake of serotonin may exacerbate the adverse effects of the latter and precipitate the serotonin syndrome. Sweetman SC (ed), Martindale: The Complete Drug Reference. London: Pharmaceutical Press (2009), p.427.

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There have been occasional reports of sexual disinhibition in patients taking tryptophan with phenothiazines or benzodiazepines. Sweetman SC (ed), Martindale: The Complete Drug Reference. London: Pharmaceutical Press (2009), p.427.

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For more Interactions (Complete) data for (L)-Tryptophan (16 total), please visit the HSDB record page.

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14.1.3 Toxicity Summary

Oral rat LD50: > 16 gm/kg. Investigated as a tumorigen, mutagen, reproductive effector. Symptoms of overdose include agitation, confusion, diarrhea, fever, overactive reflexes, poor coordination, restlessness, shivering, sweating, talking or acting with excitement you cannot control, trembling or shaking, twitching, and vomiting.

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14.1.4 Antidote and Emergency Treatment

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag- valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/ Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3Rd edition, Elsevier Mosby, St. Louis, MO 2005, p. 160

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/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/ Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3Rd edition, Elsevier Mosby, St. Louis, MO 2005, p. 160

Hazardous Substances Data Bank (HSDB) https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 43/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/ Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3Rd edition, Elsevier Mosby, St. Louis, MO 2005, p. 160-1

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14.1.5 Human Toxicity Excerpts

/HUMAN EXPOSURE STUDIES/ Serotonin and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in human blood and brain cerebrospinal fluid (CSF) increase /were found/ after tryptophan loading, which is similar to the effects of L-tryptophan in animals. ... Elevations in blood and 5-HIAA and CSF serotonin after single doses of 3 or 6 g of L-tryptophan. However, ... a double- blind, placebo-controlled trial in six normal men fed 3 g/day of L-tryptophan in divided doses with meals for 3 days, found a 113% elevation in plasma tryptophan, but no changes in platelet or plasma serotonin or in plasma catecholamines. ... No changes in urinary catecholamines /were found/. Additionally, no changes in blood pressure, heart rate, plasma sodium levels or 24- hour sodium excretion in urine /were found/. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 732, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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/HUMAN EXPOSURE STUDIES/ L-Tryptophan administration (2 g) as a single dose before a meal has been found to decrease subjective hunger ratings, food intake, and alertness in men, but not women. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 732, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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/HUMAN EXPOSURE STUDIES/ 15 humans /were tested/ only once with 0, 1, 2, and 3 g of L-tryptophan. Individuals receiving 2 and 3 g of L-tryptophan had decreased hunger and alertness and increased faintness and dizziness. Administration of 1 g of L-tryptophan with 10 g of carbohydrates before each meal (3 g L-tryptophan/d) for 3 months did not affect body weight of obese humans. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 732, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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/HUMAN EXPOSURE STUDIES/ Daily doses of 2.4 g of L-tryptophan for 2 weeks did not produce a significant reduction in the consumption of carbohydrate snacks in the majority of the 24 individuals. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 732-733, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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For more Human Toxicity Excerpts (Complete) data for (L)-Tryptophan (19 total), please visit the HSDB record page.

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14.1.6 Non-Human Toxicity Excerpts

/LABORATORY ANIMALS: Acute Exposure/ The hematologic and pathologic effects of orally administered L-tryptophan and indoleacetic acid and of L-tryptophan administered iv were studied in ponies. Sixteen adult Shetland ponies were allotted into 4 experimental groups. Group 1 consisted of 5 ponies (1-5) given 0.6 g of tryptophan/kg of body weight in a water slurry via stomach tube. Group 2 included 4 ponies (6-9) given 0.35 g of tryptophan/kg orally. Group 3 ponies (10-13) were given 0.35 g of indoleacetic acid/kg orally. Group 4 consisted of 3 ponies (14-16) given a single 4 hr iv infusion of 0.1 g of tryptophan/kg. Restlessness, increased respiratory rate, hemolysis, and hemoglobinuria were detected in 4 of the 5 group-1 ponies. Only pony 7 in group 2 developed hemolysis, hemoglobinuria, and a significant increase in respiratory rate. Renal pathologic lesions, consistent with hemoglobinuric nephrosis, were seen in ponies 2, 4, 5, and 7. Bronchiolar degeneration was evident in 4 of 9 ponies given tryptophan orally. The importance of these respiratory lesions was unknown. Clinical or pathologic abnormalities were not noticed in the ponies of groups 3 and 4. Mean plasma tryptophan values increased significantly in groups 1 and 2 at 6 hours after dosing. A second peak of tryptophan was detected in both groups at 12 hours. Values returned to predose values by 48 hours. Plasma indole and 3-methylindole concentrations were detectable in only 2 ponies (4 and 7). In vitro incubations of cecal fluid from ponies 6, 8, and 9 yielded a percentage conversion of tryptophan to indole of 16.75%, 5.84%, and 7.96% respectively. 3-Methylindole was not produced. These results suggested that indole was the major metabolite of orally administered tryptophan in these ponies. PMID:1854100 Paradis MR et al; Am J Vet Res 52 (5): 742-7 (1991).

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/LABORATORY ANIMALS: Acute Exposure/ High L-tryptophan concentrations, similar to those found in hypertryptophanemic patients were induced by three subcutaneous injections of saline- buffered tryptophan (2 umol/g body weight) to 30-day-old Wistar rats. The parameters were assessed 1 hr after the last injection. It was observed that tryptophan significantly increased thiobarbituric acid-reactive substances, 2',7'-dihydrodichlorofluorescein oxidation and reduced glutathione, whereas it reduced catalase activity. Pre-treatment with taurine (1.6 umol/g of body weight), or alpha-tocopherol plus ascorbic acid (40 and 100 ug/g body weight, respectively) prevented those effects of tryptophan, reinforcing the hypothesis that tryptophan induces oxidative stress in brain cortex of the rats... Feksa LR et al; Metabol Brain Dis 23 (2): 221-33 (2008). Available from, as of March 17, 2010: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=18425567

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/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Several rodent studies have demonstrated that supplementation of low-protein diets with L-tryptophan (5%) reduces food intake and weight gain over a 4-day to 4-week period found that rats given a 20% casein diet supplemented with 14.3% tryptophan for 4 weeks developed scaly tails and thinning hair. However, no adverse effects were seen when the diets contained 1.4 or 2.9% L-tryptophan. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 732, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

Hazardous Substances Data Bank (HSDB) https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 44/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ In pigs, supplementation with 0.1 or 1% L-tryptophan for up to 40 days did not affect weight gain, but 2 or 4% decreased weight gain and 4% also decreased food intake. NAS, Food and Nutrition Board, Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press, Washington, D.C., pg. 732, 2009. Available from, as of March 10, 2010: http://www.nap.edu/catalog/10490.html

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For more Non-Human Toxicity Excerpts (Complete) data for (L)-Tryptophan (22 total), please visit the HSDB record page.

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14.1.7 Non-Human Toxicity Values

LD50 Rat ip 1634 mg/kg Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 3632

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LD50 Mouse ip 4800 mg/kg Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 3632

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14.1.8 Ongoing Test Status

The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical.[Available from: http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm? fuseaction=ntpsearch.searchresults&searchterm=73-22-3]

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14.1.9 National Toxicology Program Studies

A bioassay of the amino acid L-tryptophan for possible carcinogenicity was conducted by administering the test compound to Fischer 344 rats and B6C3F1 mice. Groups of 35 rats and 35 mice of each sex were administered the test compound at one of two doses, either 25,000 or 50,000 ppm, 5 day/wk for 78 wk, and then observed for 26 or 27 wk. Matched controls consisted of groups of 15 rats or 15 mice of each sex. All surviving rats and mice were sacrificed at 104 or 105 wk ... No neoplasms occurred in a statistically significant incidence among dosed rats when compared with controls. In both male and female mice, neoplasms of the hematopoietic system occurred at higher incidences in the low dose groups than in the matched control groups ... These incidences, however, are not statistically significant, ... therefore, no tumors are considered to be related to the administration of the test chemical ... It is concluded that under the conditions of this bioassay, L-tryptophan was not carcinogenic for Fischer 344 rats or B6C3F1 mice. DHEW/NCI; Bioassay of L-Tryptophan for Possible Carcinogenicity p.vii (1978) Technical Rpt Series No. 071 DHEW Pub No. (NIH) 78-1321

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14.2 Ecological Information

14.2.1 Environmental Fate/Exposure Summary

(L)-Tryptophan's production and use in nutrition and research, in medicine, as a dietary supplement, and in cereal enrichment may result in its release to the environment through various waste streams. The compound is an essential amino acid for human development. If released to air, an estimated vapor pressure of 2.1X10-9 mm Hg at 25 °C indicates (L)-tryptophan will exist solely in the particulate phase in the atmosphere. Particulate-phase (L)-tryptophan will be removed from the atmosphere by wet or dry deposition. (L)-Tryptophan in aqueous solution is susceptible to direct photolysis by sunlight, with the oxidation products kynurenine and N-formylkynurenine accumulated most readily at pH 4-7.5. If released to soil, (L)-tryptophan is expected to have moderate mobility based upon an estimated Koc of 320. The pKa values of pKa1 2.38 (carboxylic acid) and pKa2 9.39 (primary amine) indicate that this compound will exist as a zwitterion which may affect its adsorption to soils and sediments. Volatilization from moist soil is not expected because ions do not volatilize. (L)-Tryptophan may not volatilize from dry soil surfaces based upon its vapor pressure. Using the Warburg respirometer test, theoretical BOD values of 4.6% in 24 hours suggest that biodegradation is not expected to be an important environmental fate process. If released into water, (L)-tryptophan may adsorb to suspended solids and sediment based upon the estimated Koc. The pKa values indicate (L)-tryptophan will exist as a zwitterion at pH values of 5 to 9 and therefore volatilization from water surfaces is not expected to be an important fate process. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to (L)-tryptophan may occur through inhalation and dermal contact with this compound at workplaces where (L)-tryptophan is produced or used. Use data indicate that the general population may be exposed to (L)-tryptophan via ingestion of food, medications and other consumer products containing (L)-tryptophan. (SRC)

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14.2.2 Natural Pollution Sources

(L)-Tryptophan is an essential amino acid for human development and a precursor of serotonin(1). (1) O'Neil MJ, ed; The Merck Index. 14th ed., Whitehouse Station, NJ: Merck and Co., Inc., p. 1683 (2006)

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MILK & EGGS ... HAVE HIGH TRYPTOPHAN CONTENT. Furia, T.E. (ed.). CRC Handbook of Food Additives. 2nd ed. Cleveland: The Chemical Rubber Co., 1972., p. 89

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14.2.3 Artificial Pollution Sources https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 45/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

(L)-Tryptophan's production and use in nutrition and research, in medicine, as a dietary supplement, and in cereal enrichment(1) may result in its release to the environment through various waste streams(SRC). (1) Lewis RJ Sr; Hawley's Condensed Chemical Dictionary 15th ed. New York, NY: John Wiley & Sons, Inc., p. 1292 (2007)

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14.2.4 Environmental Fate

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 320(SRC), determined from a log Kow of -1.06(2) and a regression-derived equation(3), indicates that (L)- tryptophan is expected to have moderate mobility in soil(SRC). The pKa values of pKa1 2.38 (carboxylic acid) and pKa2 9.39 (primary amine)(4) indicate that this compound will exist as a zwitterion which may affect its adsorption to soils and sediments(SRC). Volatilization from moist soil is not expected because ions do not volatilize(SRC). Volatilization from moist soil is not expected because the acid/base exists as an anion/cation and anions/cations do not volatilize. (L)-Tryptophan is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.1X10-9 mm Hg at 25 °C(SRC), determined from a fragment constant method(5). Using the Warburg respirometer test, a theoretical BOD value of 4.6% in 24 hours(6) suggests that biodegradation is not expected to be an important environmental fate process in soil(SRC). (1) Swann RL et al; Res Rev 85: 17-28 (1983) (2) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Soc p. 84 (1995) (3) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.0. Jan, 2009. Available from http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm as of Feb 17, 2010. (4) O'Neil MJ, ed; The Merck Index., 14th ed., Whitehouse Station, NJ: Merck and Co., Inc., p. 1683 (2006) (5) Lyman WJ; p. 31 in Environmental Exposure From Chemicals Vol I, Neely WB, Blau GE, eds, Boca Raton, FL: CRC Press (1985) (6) Malaney GW, Gerhold RM; J Water Pollut Control Fed 41: R18-R33 (1969)

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AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 320(SRC), determined from a log Kow of -1.06(2) and a regression-derived equation(3), indicates that (L)- tryptophan may adsorb to suspended solids and sediment(SRC). The pKa values of pKa1 2.38 (carboxylic acid) and pKa2 9.39 (primary amine)(4) indicate (L)-tryptophan will exist as a zwitterion at pH values of 5 to 9 and therefore volatilization from water surfaces is not expected to be an important fate process(5). According to a classification scheme(6), an estimated BCF of 3(SRC), from its log Kow(2) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Using the Warburg respirometer test, a theoretical BOD value of 4.6% in 24 hours(8) suggests that biodegradation is not expected to be an important environmental fate process in water(SRC). (1) Swann RL et al; Res Rev 85: 17-28 (1983) (2) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Soc p. 84 (1995) (3) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.0. Jan, 2009. Available from http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm as of Feb 17, 2010. (4) O'Neil MJ, ed; The Merck Index.,14th ed. Whitehouse Station, NJ: Merck and Co., Inc., p. 1683 (2006) (5) Doucette WJ; pp. 141-188 in Handbook of Property Estimation Methods for Chemicals. Boethling RS, Mackay D, eds, Boca Raton, FL: Lewis Publ (2000) (6) Franke C et al; Chemosphere 29: 1501-14 (1994) (7) Meylan WM et al; Environ Toxicol Chem 18: 664-72 (1999) (8) Malaney GW, Gerhold RM; J Water Pollut Control Fed 41: R18-R33 (1969)

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ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), (L)-tryptophan, which has an estimated vapor pressure of 2.1X10-9 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase (L)- tryptophan may be removed from the air by wet or dry deposition(SRC). Photooxidation proceeds primarily by a singlet-oxygen mechanism(3). The oxidation products kynurenine and N- formylkynurenine accumulated most readily at pH 4-7.5 following irradiation of solutions of tryptophan containing riboflavin(4). (1) Bidleman TF; Environ Sci Technol 22: 361-367 (1988) (2) Lyman WJ; p. 31 in Environmental Exposure From Chemicals Vol I, Neely WB, Blau GE, eds, Boca Raton, FL: CRC Press (1985) (3) Nilsson R et al; Photochem Photobiol 16: 117-24 (1972) (4) Kanner JD, Fennema O; J Agric Food Chem 35: 71-6 (1987)

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14.2.5 Environmental Biodegradation

AEROBIC: At 500 ppm, theoretical BOD values of 0.6, 1.4, and 4.6% in 6, 12, and 24 hours, respectively, were measured for (L)-tryptophan after a 24-hr inoculation period in a Warburg respirometer using an activated sludge inocula, indicating a resistence to biodegradation(1). (1) Malaney GW, Gerhold RM; J Water Pollut Control Fed 41: R18-R33 (1969)

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14.2.6 Environmental Abiotic Degradation

(L)-Tryptophan is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(1). (L)-Tryptophan in aqueous solution was shown to photodegrade readily over six hours using both an HPLN-N 125 W Phillips lamp as a the near-UV source and natural sunlight(2). Photooxidation proceeds primarily by a singlet-oxygen mechanism(3). The oxidation products kynurenine and N-formylkynurenine accumulated most readily at pH 4-7.5 following irradiation of solutions of tryptophan containing riboflavin(4). (1) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 7-4, 7-5 (1990) (2) Jardim WF, Campos MLAM; Sci Total Environ 75: 243-8 (1988) (3) Nilsson R et al; Photochem Photobiol 16: 117-24 (1972) (4) Kanner JD, Fennema O; J Agric Food Chem 35: 71-6 (1987)

Hazardous Substances Data Bank (HSDB)

14.2.7 Environmental Bioconcentration

An estimated BCF of 3 was calculated in fish for (L)-tryptophan(SRC), using a log Kow of -1.06(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC). (1) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Soc p. 84 (1995) (2) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.0. Jan, 2009. Available from http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm as of Feb 17, 2010. (3) Franke C et al; Chemosphere 29: 1501-14 (1994)

Hazardous Substances Data Bank (HSDB)

14.2.8 Soil Adsorption/Mobility

The Koc of (L)-tryptophan is estimated as 320(SRC), using a log Kow of -1.06(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that (L)-tryptophan is expected to have moderate mobility in soil. The pKa values of pKa1 2.38 (carboxylic acid) and pKa2 9.39 (primary amine)(4) indicate that this compound will exist as a zwitterion which may affect its adsorption to soils and sediments(SRC). (1) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Soc p. 84 (1995) (2) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.0. Jan, 2009. Available from http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm as of Feb 17, 2010. (3) Swann RL et al; Res Rev 85: 17-28 (1983) (4) O'Neil MJ, ed; The Merck Index., 14th ed. Whitehouse Station, NJ: Merck and Co., Inc., p. 1683 (2006)

Hazardous Substances Data Bank (HSDB) https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 46/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

14.2.9 Volatilization from Water/Soil

The pKa values of pKa1 2.38 (carboxylic acid) and pKa2 9.39 (primary amine)(1) indicate (L)-tryptophan will exist as a zwitterion at pH values of 5 to 9 and therefore volatilization from water surfaces is not expected to be an important fate process(2). (L)-Tryptophan is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.1X10-9 mm Hg(SRC), determined from a fragment constant method(3). (1) O'Neil MJ, ed; The Merck Index., 14th ed. Whitehouse Station, NJ: Merck and Co., Inc., p. 1683 (2006) (2) Doucette WJ; pp. 141-188 in Handbook of Property Estimation Methods for Chemicals. Boethling RS, Mackay D, eds. Boca Raton, FL: Lewis Publ (2000) (3) Lyman WJ; p. 31 in Environmental Exposure From Chemicals Vol I, Neely WB, Blau GE, eds, Boca Raton, FL: CRC Press (1985)

Hazardous Substances Data Bank (HSDB)

14.2.10 Plant Concentrations

Plant species with highest amount of tryptophan(1). /Tryptophan/

Area of Genus species Common name(s) Concentration Plant

2,400 - 16,000 Oenothera biennis L. Evening-Primrose Seed ppm

7,037 - 15,900 Helianthus annuus L. Girasol, Sunflower Seed ppm

Psophocarpus tetragonolobus 7,620 - 8,313 Asparagus Pea, Goa Bean, Winged Bean Seed (L.) DC. ppm

880 - 7,255 Lablab purpureus (L.) SWEET Bonavist Bean, Hyacinth Bean, Lablab Bean Seed ppm

1,440 - 6,745 Moringa oleifera LAM. Ben Nut, Benzolive Tree, Drumstick Tree, Horseradish Tree, Jacinto (Sp.), Moringa, West Indian Ben Shoot ppm

300 - 6,000 Nasturtium officinale R. BR. Berro, Watercress Herb ppm

Psophocarpus tetragonolobus 2,520 - 5,915 Asparagus Pea, Goa Bean, Winged Bean Tuber (L.) DC. ppm

5,260 - 5,628 Sinapis alba L. White Mustard Seed ppm

1,840 - 5,472 Cucurbita foetidissima HBK. Buffalo Gourd Seed ppm

Psophocarpus tetragonolobus 1,160 - 5,011 Asparagus Pea, Goa Bean, Winged Bean Leaf (L.) DC. ppm

1,850 - 4,970 Cicer arietinum L. Chickpea, Garbanzo Seed ppm

2,010 - 4,969 Sesamum indicum L. Ajonjoli (Sp.), Beni, Benneseed, Sesame, Sesamo (Sp.) Seed ppm

Phaseolus vulgaris subsp. var. Black Bean, Dwarf Bean, Field Bean, Flageolet Bean, French Bean, Garden Bean, Green Bean, Haricot, Haricot Bean, Haricot Vert, Kidney Bean, Navy 440 - 4,731 Sprout vulgaris Bean, Pop Bean, Popping Bean, Snap Bean, String Bean, Wax Bean ppm Seedling

390 - 4,632 Spinacia oleracea L. Spinach Plant ppm

4,310 - 4,630 Cucurbita pepo L. Pumpkin Seed ppm

2,800 - 4,300 Trigonella foenum-graecum L. Alholva (Sp.), Bockshornklee (Ger.), Fenugreek, Greek Clover, Greek Hay Seed ppm

280 - 4,060 Basella alba L. Vinespinach Leaf ppm

300 - 4,000 Corchorus olitorius L. Jew's Mallow, Mulukiya, Nalta Jute Leaf ppm

Brassica nigra (L.) W. D. J. 270 - 3,976 Black Mustard Leaf KOCH ppm

370 - 3,886 Sprout Vigna radiata (L.) WILCZEK Green Gram, Mungbean ppm Seedling

310 - 3,875 Allium schoenoprasum L. Chives Leaf ppm

300 - 3,871 Asparagus officinalis L. Asparagus Shoot ppm

3,660 - 3,786 Juglans cinerea L. Butternut Seed ppm

Prunus dulcis (MILLER) D. A. 3,580 - 3,745 Almond Seed WEBB ppm

310 - 3,729 Amaranthus sp. Pigweed Leaf ppm

Eryngium creticus Cretan culantro 3,715 ppm Shoot

180 - 3,672 Cichorium intybus L. Chicory, Succory, Witloof Leaf ppm

Valerianella locusta (L.) 260 - 3,610 Corn Salad, Lamb's Lettuce Plant LATERRADE ppm

160 - 3,400 Portulaca oleracea L. Purslane, Verdolaga Herb ppm

Brassica oleracea var. botrytis l. 260 - 3,360 Cauliflower Flower var. botrytis L. ppm

(1) USDA; Dr. Duke's Phytochemical and Ethnobotanical Databases. Plants with a chosen chemical. Isoleucine. Washington, DC: US Dept Agric, Agric Res Service. Available from, as of August 13, 2010: http://www.ars- grin.gov/duke/

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14.2.11 Milk Concentrations

Concentrations of tryptophan (free and protein bound) and its metabolites in ... breast milk were determined by high performance liquid chromatography. ... The colostrum contained a high level of total tryptophan. There were high ratios of free to total tryptophan in colostrum, transitional and mature milk. ... PMID:1867111 Kamimira S et al; Acta Med Okayama Apr; 45(2): 101-6 (1991). Available from as of Aug 13, 2010:

Hazardous Substances Data Bank (HSDB)

14.2.12 Probable Routes of Human Exposure

NIOSH (NOES Survey 1981-1983) has statistically estimated that 24,809 workers (2,015 of these were female) were potentially exposed to (L)-tryptophan in the US(1). Occupational exposure to (L)-tryptophan may occur through inhalation and dermal contact with this compound at workplaces where (L)-tryptophan is produced or used. Use data indicate that the general population may be exposed to (L)-tryptophan via ingestion of food and other consumer products containing (L)-tryptophan(SRC). (1) NIOSH; NOES. National Occupational Exposure Survey conducted from 1981-1983. Estimated numbers of employees potentially exposed to specific agents by 2-digit standard industrial classification (SIC). Available from, as of Feb 17, 2010: http://www.cdc.gov/noes/

Hazardous Substances Data Bank (HSDB)

14.2.13 Body Burden

Concentrations of tryptophan (free and protein bound) and its metabolites in plasma of maternal vein at delivery, umbilical vein, umbilical artery, neonatal vein and breast milk were determined by high performance liquid chromatography. The plasma levels of tryptophan and most of its metabolites in umbilical vein and artery were significantly higher than those in maternal vein. The concentration of total tryptophan in plasma of neonatal vein showed marked decrease at 24 h after birth in comparison with that at birth, but the total kynurenine concentration was not decreased in plasma of neonatal vein. The colostrum contained a high level of total tryptophan. There were high ratios of free to total tryptophan in colostrum, transitional and mature milk. In the blood, ratios of free to total of tryptophan and kynurenine were kept at constant level throughout the perinatal period. PMID:1867111 Kamimira S et al; Acta Med Okayama Apr; 45(2): 101-6 (1991). Available from as of Aug 13, 2010:

Hazardous Substances Data Bank (HSDB)

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 48/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

15 Associated Disorders and Diseases

Comparative Toxicogenomics Database (CTD)

Disease References

PubMed: 14992292, 7869898, 12121313, 10534261, 6198481, 1705463, 7126379, 15993662, 803305, Epilepsy 10577274, 19817812, 10688964, 436860

PubMed: 115032, 7126379, 2480613, 17276036, 11877547, 12796220, 7595563, 20814316, 25004141, 24713860, 23823132, 2415198, 1694425, 7711000, 19390223, 22024767, 22007635, 21483431, 3741918, Schizophrenia 11979513, 20206656, 436860, 19401681, 6184954, 26952797, 22800120, 24789758, 22944140, 22892715, 17440431, 25729574, 22257447

PubMed: 17031479, 11959400, 8595727, 15361288, 9693263, 15465626, 15061359, 10494443, 11255442, Alzheimer's disease 12498967, 16227558, 9720975, 12111441, 16244393, 8356878, 12391605, 8478958, 21292280, 20858978, 21474939, 20523031, 11314776, 1716470, 23857558

PubMed: 7482520, 19006102, 23940645, 24424155, 20156336, 19678709, 22148915, 25105552, 21773981, 25037050, 27015276, 27107423, 27275383, 28587349 Colorectal cancer Silke Matysik, Caroline Ivanne Le Roy, Gerhard Liebisch, Sandrine Paule Claus. Metabolomics of fecal samples: A practical consideration. Trends in Food Science & Technology. Vol. 57, Part B, Nov. 2016, p.244-255: http://www.sciencedirect.com/science/article/pii/S0924224416301984

Ovarian cancer PubMed: 7482520, 15818726, 22309680, 19010317, 26573008

PubMed: 15899597, 16253646, 2401584, 17264178, 1783639, 26505825, 17408529, 18997681, 24740590, Obesity 23108202, 26910390 Metabolomics reveals determinants of weight loss during lifestyle intervention in obese children

Nicotinamide Adenine Dinucleotide Deficiency PubMed: 28792876

Hartnup disease PubMed: 2472426

Leukemia PubMed: 9464484, 1184685, 15911239, 7482520, 11129502

Olivopontocerebral atrophy PubMed: 1538220, 11383938

Hereditary spastic paraplegia PubMed: 11383938

Hypothyroidism PubMed: 9849813, 9284897, 8421080, 3988241, 7256725

Friedreich's ataxia PubMed: 1538220, 11383938

Celiac disease PubMed: 3816078, 16425363, 10063930, 6182605, 6182788, 24657864, 21970810, 27452636

Irritable bowel syndrome PubMed: 9505884, 8723414, 21330412, 21761941, 21494186, 23867873, 27662586

PubMed: 21059682, 1740537, 17269711, 17314143, 21761941, 23516449, 23867873, 24811995, 25598765, Ulcerative colitis 26806034, 26848182, 27609529, 28842642

Autism PubMed: 20423563, 7687150, 6150139, 15585776, 3410814, 12205654, 24130822

PubMed: 16440420, 11418788, 8723414, 19491857, 17269711, 23516449, 23867873, 24811995, 25598765, Crohn's disease 26806034, 26848182, 27609529, 28842642

PubMed: 6589104, 16277678, 15338487, 10361015, 15249323

Rheumatoid arthritis Tie-juan ShaoZhi-xing HeZhi-jun XieHai-chang LiMei-jiao WangCheng-ping Wen. Characterization of ankylosing spondylitis and rheumatoid arthritis using 1H NMR-based metabolomics of human fecal extracts. Metabolomics. April 2016, 12:70: https://link.springer.com/article/10.1007/s11306-016-1000-2

PubMed: 17668437, 15607313, 14569192, 10379660, 17403619, 22284503, 20300169, 22061338, Perillyl alcohol administration for cancer treatment 19783829, 19010317

Pancreatic cancer PubMed: 2315288, 20300169, 22613268, 21505807, 25429707

Periodontal disease PubMed: 20300169

Frontotemporal dementia PubMed: 23857558

Lewy body disease PubMed: 23857558

Attachment loss PubMed: 31026179

Periodontal Probing Depth PubMed: 31026179

Cachexia PubMed: 18953024, 11320368

Eosinophilic esophagitis Mordechai, Hien, and David S. Wishart

Tryptophanuria with dwarfism PubMed: 14055140

Human Metabolome Database (HMDB) https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 49/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 50/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

16 Literature

16.1 Coronavirus Studies

22 items View More Rows & Details

SORT BY Publication Date

Title Publication Name Publication Date PMID

The molecular mechanism of domain-swapping of the C-terminal domain of the SARS coronavirus main protease Biophysical journal 2020-12-24 33359834

Increased kynurenine-to-tryptophan ratio in the serum of patients infected with SARS-CoV2: An observational cohort Biochimica et biophysica acta. Molecular basis of 2020-12-16 33338598 study disease

Structural and functional comparison of SARS-CoV-2-spike receptor binding domain produced in Pichia pastoris and Scientific reports 2020-12-11 33311634 mammalian cells

Serum neopterin levels in relation to mild and severe COVID-19 BMC infectious diseases 2020-12-10 33302893

Diverse chemical space of indoleamine-2,3-dioxygenase 1 (Ido1) inhibitors European journal of medicinal chemistry 2020-12-02 33341650

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PubChem

16.2 NLM Curated PubMed Citations

PubChem

16.3 Springer Nature References

Springer Nature

16.4 Thieme References

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 51/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Thieme Chemistry

16.5 Wiley References

Wiley

16.6 Depositor Provided PubMed Citations

17,479 items View More Rows & Details

SORT BY Publication Date

PMID Publication Date Title Journal

Effects of Prenatal Exposure to a Mixture of Organophosphate Flame Retardants on Placental Gene Expression and Toxicological sciences : an official journal of the 32243540 2020-07-01 Serotonergic Innervation in the Fetal Rat Brain Society of Toxicology

Identification of key metabolites during cisplatin-induced acute kidney injury using an HPLC-TOF/MS-based non-targeted 31926187 2020-02-15 Toxicology urine and kidney metabolomics approach in rats

29968805 2018-07-03 Insights into myalgic encephalomyelitis/chronic fatigue syndrome phenotypes through comprehensive metabolomics Scientific reports

28798976 2017-10-01 5-HT modulation of pain perception in humans Psychopharmacology

28830789 2017-10-01 New amide and dioxopiperazine derivatives from leaves of Breynia nivosa Fitoterapia

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PubChem

16.7 Synthesis References

Sten Vilhelm Gatenbeck, Per Olof Hedman, "Fermentative process for the production of L-tryptophan and its derivatives." U.S. Patent US3963572, issued April, 1974.

DrugBank

Amir-Heidari, Bagher; Thirlway, Jenny; Micklefield, Jason. Stereochemical course of tryptophan dehydrogenation during biosynthesis of the calcium-dependent lipopeptide antibiotics. Organic Letters (2007), 9(8), 1513-1516.

Human Metabolome Database (HMDB)

16.8 Metabolite References

218 items View More

PMID Reference

14992292 Rainesalo S, Keranen T, Palmio J, Peltola J, Oja SS, Saransaari P: Plasma and cerebrospinal fluid amino acids in epileptic patients. Neurochem Res. 2004 Jan;29(1):319-24.

Cady EB, Lorek A, Penrice J, Reynolds EO, Iles RA, Burns SP, Coutts GA, Cowan FM: Detection of propan-1,2-diol in neonatal brain by in vivo proton magnetic resonance spectroscopy. Magn Reson Med. 7869898 1994 Dec;32(6):764-7. https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 52/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

PMID Reference

12121313 Perosa SR, Porcionatto MA, Cukiert A, Martins JR, Amado D, Nader HB, Cavalheiro EA, Leite JP, Naffah-Mazzacoratti MG: Extracellular matrix components a

Spanaki MV, Siegel H, Kopylev L, Fazilat S, Dean A, Liow K, Ben-Menachem E, Gaillard WD, Theodore WH: The effect of vigabatrin (gamma-vinyl GABA) on cerebral blood flow and metabolism. 10534261 Neurology. 1999 Oct 22;53(7):1518-22.

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Human Metabolome Database (HMDB)

16.9 General References

Balibar et al. Terrequinone A biosynthesis through L-tryptophan oxidation, dimerization and bis-prenylation Nature Chemical Biology, doi: 10.1038/NChemBio.2007.20, published online 12 August 2007. http://www.nature.com/naturechemicalbiology

Nature Chemical Biology

Volgraf et al. Biomimetic Synthesis of the IDO Inhibitors Exiguamine A and B Nature Chemical Biology, doi: 10.1038/nchembio.107, published online 3 August 2008. http://www.nature.com/naturechemicalbiology

Nature Chemical Biology

Yuan et al. Absolute Metabolite Concentrations and Implied Enzyme Active Site Occupancy in Escherichia coli Nature Chemical Biology, doi: 10.1038/nchembio.186, published online 28 June 2009 http://www.nature.com/naturechemicalbiology

Nature Chemical Biology

Yan et al. Extracellular redox modulation by regulatory T cells. Nature Chemical Biology, doi: 10.1038/nchembio.212, published online 30 August 2009 http://www.nature.com/naturechemicalbiology

Nature Chemical Biology

Lim et al. Targeting the interaction of AIMP2-DX2 with HSP70 suppresses cancer development. Nature Chemical Biology, doi: 10.1038/s41589-019-0415-2, published online 2 December 2019

Nature Chemical Biology

Hein et al. A route to enantiopure RNA precursors from nearly racemic starting materials. Nature Chemistry, doi: 10.1038/nchem.1108, published online 7 August 2011 http://www.nature.com/nchem

Nature Chemistry

16.10 Chemical Co-Occurrences in Literature

PubChem

16.11 Chemical-Gene Co-Occurrences in Literature

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PubChem

16.12 Chemical-Disease Co-Occurrences in Literature

PubChem

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17 Patents

17.1 Depositor-Supplied Patent Identifiers

PubChem

Link to all deposited patent identifiers

PubChem

17.2 WIPO PATENTSCOPE

Patents are available for this chemical structure:

https://patentscope.wipo.int/search/en/result.jsf?inchikey=QIVBCDIJIAJPQS-VIFPVBQESA-N

PATENTSCOPE (WIPO)

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 55/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

18 Biomolecular Interactions and Pathways

18.1 Protein Bound 3-D Structures

RCSB Protein Data Bank (RCSB PDB)

View 146 proteins in NCBI Structure

PubChem

18.2 Drug-Gene Interactions

Drug Gene Interaction database (DGIdb)

18.3 Chemical-Gene Interactions

18.3.1 CTD Chemical-Gene Interactions

Comparative Toxicogenomics Database (CTD)

18.4 DrugBank Interactions

11 items View More Rows & Details https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 56/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

Drug Actions Target Name PubChem Protein PubChem Gene General Function Specific Function Evidence PMID

17114825 17428498 Tryptophan--tRNA Tryptophan-trna inhibitor ligase, Q9UGM6 WARS2 16639024 ligase activity mitochondrial 16724112 16636268

17150540 17428498 Tryptophan--tRNA Tryptophan-trna inhibitor P23381 WARS Isoform 1, isoform 2 and T1-TrpRS have aminoacylation activity while T2-TrpRS lacks it. 17114500 ligase, cytoplasmic ligase activity 17661345 16724112

Tryptophan 2,3- Incorporates oxygen into the indole moiety of tryptophan. Has a broad specificity towards Tryptophan 2,3- substrate P48775 TDO2 dioxygenase tryptamine and derivatives including D- and L-tryptophan, 5-hydroxytryptophan and 19290871 dioxygenase activity serotonin (By similarity) DrugBank

18.5 Drug-Drug Interactions

DrugBank

18.6 Pathways

PubChem

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 57/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

19 Biological Test Results

19.1 BioAssay Results

1,298 items View More Rows & Details

SORT BY Activity Value

Activity Activity Value, µM Activity Type Target Name BioAssay Name BioAssay AID Substance SID

Activity of Sulfurihydrogenibium yellowstonense YO3AOP1 recombinant CA expressed in Active 0.007 KA Escherichia coli BL21(DE3) after 15 mins by phenol red staining based stopped flow CO2 691715 103241616 hydration assay

Activation of Sulfurihydrogenibium yellowstonense recombinant CA by stopped flow Active 0.007 KA 725227 103241616 CO2 hydrase method

Activation of Sulfurihydrogenibium azorense recombinant alpha carbonic anhydrase by Active 0.023 KA 725226 103241616 stopped flow CO2 hydrase method

qHTS assay to identify small molecule antagonists of the vitamin D receptor (VDR) Inconclusive 0.0275 Potency 743225 144210677 signaling pathway - cell viability counter screen

ESRRA - estrogen qHTS assay to identify small molecule antagonists of the estrogen related receptor Inconclusive 0.1725 Potency related receptor alpha signaling pathway with the pleiotropic PPARgamma coactivator (PGC) from Tox21 10K 1224841 144208444 (human) library

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PubChem

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20 Classification

20.1 Ontologies

20.1.1 MeSH Tree

Medical Subject Headings (MeSH)

20.1.2 ChEBI Ontology

ChEBI

20.1.3 KEGG: Metabolite

KEGG

20.1.4 KEGG: ATC

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 59/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

KEGG

20.1.5 KEGG: JP15

KEGG

20.1.6 KEGG: Risk Category of Japanese OTC Drugs

KEGG

20.1.7 KEGG: Drug Classes

KEGG https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 60/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

20.1.8 WHO ATC Classification System

WHO Anatomical Therapeutic Chemical (ATC) Classification

20.1.9 ChemIDplus

ChemIDplus

20.1.10 CAMEO Chemicals

CAMEO Chemicals

20.1.11 Guide to PHARMACOLOGY Target Classification

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 61/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

IUPHAR/BPS Guide to PHARMACOLOGY

20.1.12 ChEMBL Target Tree

Showing 5 of 16 View More

Enzyme Biological molecules that possess catalytic activity. They may occur naturally or be synthetically created. Enzymes are usually proteins, however CATALYTIC RNA and CATALYTIC DNA molecules have also been identified. [MESH:D004798] LINKED RECORDS undefined: 174,056 undefined: 454,123 undefined: 3,391 undefined: 4,417 undefined: 21,965 undefined: 455,647 undefined: 433 CLASSIFICATION (PARENT NODES) Target Tree

Secreted protein

LINKED RECORDS undefined: 2,012 undefined: 6,453 undefined: 139 undefined: 142 undefined: 520 undefined: 6,479 undefined: 14 CLASSIFICATION (PARENT NODES) Target Tree

Oxidoreductase The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9) [MESH:D010088] LINKED RECORDS undefined: 15,851 undefined: 59,974 undefined: 466 undefined: 565 undefined: 3,408 undefined: 60,197 undefined: 101 CLASSIFICATION (PARENT NODES)

Target Tree Enzyme

Metallo protease M10A subfamily A member of the metalloproteinase family of enzymes that is principally responsible for cleaving FIBRILLAR COLLAGEN. It can degrade interstitial collagens, types I, II and III. [MESH:D020781] LINKED RECORDS undefined: 2,948 undefined: 9,178 undefined: 31 undefined: 31 undefined: 513 undefined: 9,217 undefined: 5 CLASSIFICATION (PARENT NODES)

Target Tree Enzyme Protease Metallo Protease Metallo Protease MAM Clan

Cytochrome P450 3A4

LINKED RECORDS undefined: 3,569 undefined: 12,590 undefined: 1 undefined: 1 undefined: 2,093 undefined: 12,698 undefined: 1 CLASSIFICATION (PARENT NODES)

Target Tree Enzyme Cytochrome P450 Cytochrome P450 Family 3 Cytochrome P450 Family 3A

ChEMBL

20.1.13 UN GHS Classification

UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS)

20.1.14 EPA CPDat Classification https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 62/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

EPA Chemical and Products Database (CPDat)

20.1.15 NORMAN Suspect List Exchange Classification

NORMAN Suspect List Exchange

20.1.16 CCSBase Classification

CCSbase

20.1.17 EPA DSSTox Classification

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 63/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

EPA DSSTox

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 64/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

21 Information Sources

FILTER BY SOURCE ALL SOURCES

1. CAMEO Chemicals LICENSE CAMEO Chemicals and all other CAMEO products are available at no charge to those organizations and individuals (recipients) responsible for the safe handling of chemicals. However, some of the chemical data itself is subject to the copyright restrictions of the companies or organizations that provided the data. https://cameochemicals.noaa.gov/help/reference/terms_and_conditions.htm?d_f=false

L-TRYPTOPHAN https://cameochemicals.noaa.gov/chemical/21204 CAMEO Chemical Reactivity Classification https://cameochemicals.noaa.gov/browse/react

2. Wikipedia tryptophan https://en.wikipedia.org/wiki/Tryptophan

3. Human Metabolome Database (HMDB) LICENSE HMDB is offered to the public as a freely available resource. Use and re-distribution of the data, in whole or in part, for commercial purposes requires explicit permission of the authors and explicit acknowledgment of the source material (HMDB) and the original publication (see the HMDB citing page). We ask that users who download significant portions of the database cite the HMDB paper in any resulting publications. http://www.hmdb.ca/citing

L-Tryptophan http://www.hmdb.ca/metabolites/HMDB0000929

4. ChEBI L-tryptophan http://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:16828 ChEBI Ontology http://www.ebi.ac.uk/chebi/userManualForward.do#ChEBI%20Ontology

5. DrugBank LICENSE Creative Common's Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/legalcode) https://www.drugbank.ca/legal/terms_of_use

Tryptophan http://www.drugbank.ca/drugs/DB00150

6. NCI Thesaurus (NCIt) LICENSE Unless otherwise indicated, all text within NCI products is free of copyright and may be reused without our permission. Credit the National Cancer Institute as the source. https://www.cancer.gov/policies/copyright-reuse

Tryptophan https://ncit.nci.nih.gov/ncitbrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&ns=NCI_Thesaurus&code=C29603

7. Hazardous Substances Data Bank (HSDB) (L)-Tryptophan https://pubchem.ncbi.nlm.nih.gov/source/hsdb/4142

8. EPA DSSTox LICENSE https://www.epa.gov/privacy/privacy-act-laws-policies-and-resources

l-Tryptophan https://comptox.epa.gov/dashboard/DTXSID5021419 CompTox Chemicals Dashboard Chemical Lists https://comptox.epa.gov/dashboard/chemical_lists/

9. CCSbase L-Tryptophan CCSbase Classification https://ccsbase.net/

10. NORMAN Suspect List Exchange LICENSE Data: CC-BY 4.0; Code (hosted by ECI, LCSB): Artistic-2.0 https://creativecommons.org/licenses/by/4.0/

L-Tryptophan NORMAN Suspect List Exchange Classification https://www.norman-network.com/nds/SLE/

11. ChemIDplus LICENSE https://www.nlm.nih.gov/copyright.html

Tryptophan [USAN:INN] https://chem.nlm.nih.gov/chemidplus/sid/0000073223 ChemIDplus Chemical Information Classification https://chem.nlm.nih.gov/chemidplus/

12. DTP/NCI LICENSE https://www.cancer.gov/policies/copyright-reuse https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 65/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem p g p py g

tryptophan https://dtp.cancer.gov/dtpstandard/servlet/dwindex?searchtype=NSC&outputformat=html&searchlist=757373

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L-Tryptophan https://www.epa.gov/chemicals-under-tsca

14. European Chemicals Agency (ECHA) LICENSE Use of the information, documents and data from the ECHA website is subject to the terms and conditions of this Legal Notice, and subject to other binding limitations provided for under applicable law, the information, documents and data made available on the ECHA website may be reproduced, distributed and/or used, totally or in part, for non-commercial purposes provided that ECHA is acknowledged as the source: "Source: European Chemicals Agency, http://echa.europa.eu/". Such acknowledgement must be included in each copy of the material. ECHA permits and encourages organisations and individuals to create links to the ECHA website under the following cumulative conditions: Links can only be made to webpages that provide a link to the Legal Notice page. https://echa.europa.eu/web/guest/legal-notice

L-tryptophan https://echa.europa.eu/substance-information/-/substanceinfo/100.000.723 L-tryptophan https://echa.europa.eu/information-on-chemicals/cl-inventory-database/-/discli/details/2285

15. ClinicalTrials.gov LICENSE The ClinicalTrials.gov data carry an international copyright outside the United States and its Territories or Possessions. Some ClinicalTrials.gov data may be subject to the copyright of third parties; you should consult these entities for any additional terms of use. https://clinicaltrials.gov/ct2/about-site/terms-conditions#Use

https://clinicaltrials.gov/

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http://ctdbase.org/detail.go?type=chem&acc=D014364

17. Drug Gene Interaction database (DGIdb) LICENSE The data used in DGIdb is all open access and where possible made available as raw data dumps in the downloads section. http://www.dgidb.org/downloads

https://www.dgidb.org/drugs/TRYPTOPHAN

18. European Medicines Agency (EMA) LICENSE Information on the European Medicines Agency's (EMA) website is subject to a disclaimer and copyright and limited reproduction notices. https://www.ema.europa.eu/en/about-us/legal-notice

Soybean oil, Medium-chain triglycerides, Olive oil, Fish oil, Acetyl-cysteine, Alanine, Histidine, Isoleucin, Leucine, Lysine acetate, Methionine, Phenylalanine, Proline, Tryptophan, Tyrosine, Valine, glucose, calcium chloride, potassium chloride, Sodium acetate, Zinc sulphate, Malic acid, arginine, glycine, serine, threonine, sodium glycerophosphate, magnesium sulphate (P/0133/2017) https://www.ema.europa.eu/en/medicines/human/paediatric-investigation-plans/emea-002067-pip02-17 Alanine, arginine, aspartic acid, cysteine/cystine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine monohydrate, methionine, ornithine hydrochloride, phenylalanine, proline, serine, taurine, threonine, tryptophan, tyrosine, valine; sodium chloride, potassium acetate, magnesium acetate, tetrahydrate, calcium chloride, sodium glycerophosphate, glucose, olive oil refined, soya-bean oil refined (P/191/2009) https://www.ema.europa.eu/en/medicines/human/paediatric-investigation-plans/alanine-arginine-aspartic-acid-cysteinecystine-glutamic-acid-glycine-histidine-isoleucine-leucine N-Acetyl-L-Cysteine (corresponds to L-Cysteine), L-Alanine, L-Alanyl-L-Glutamine (corresponds to L-Alanine and L-Glutamine), L-Arginine, Glycine, Glycyl-L-Tyrosine (corresponds to Glycine and L-Tyrosine), L- Histidine, L-Isoleucine, L-Leucine, L-Lysine acetate (corresponds to L-Lysine), LMethionine, L-Phenylalanine, L-Proline, L-Serine, Taurine, L-Threonine, L-Tryptophan, L-Valine (P/175/2009) https://www.ema.europa.eu/en/medicines/human/paediatric-investigation-plans/emea-000042-pip01-07 Glycine, L-alanine, L-arginine, L-aspartic acid, L-cysteine, L-glutamic acid, L-histidine, L-lysine monohydrate, L-methionine, L-phenylalanine, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, taurine (EU/3/18/2076) https://www.ema.europa.eu/en/medicines/human/orphan-designations/eu3182076

19. EPA Chemical and Products Database (CPDat) LICENSE https://www.epa.gov/privacy/privacy-act-laws-policies-and-resources

l-tryptophan https://comptox.epa.gov/dashboard/DTXSID5021419#exposure EPA CPDat Classification https://www.epa.gov/chemical-research/chemical-and-products-database-cpdat

20. EU Clinical Trials Register https://www.clinicaltrialsregister.eu/

21. FDA Center for Food Safety and Applied Nutrition (CFSAN) LICENSE Unless otherwise noted, the contents of the FDA website (www.fda.gov), both text and graphics, are not copyrighted. They are in the public domain and may be republished, reprinted and otherwise used freely by anyone without the need to obtain permission from FDA. Credit to the U.S. Food and Drug Administration as the source is appreciated but not required. https://www.fda.gov/about-fda/about-website/website-policies#linking

L-TRYPTOPHAN https://www.cfsanappsexternal.fda.gov/scripts/fdcc/index.cfm?set=FoodSubstances&id=TRYPTOPHAN

22. FDA/SPL Indexing Data LICENSE Unless otherwise noted, the contents of the FDA website (www.fda.gov), both text and graphics, are not copyrighted. They are in the public domain and may be republished, reprinted and otherwise used freely by anyone without the need to obtain permission from FDA. Credit to the U.S. Food and Drug Administration as the source is appreciated but not required. https://www.fda.gov/about-fda/about-website/website-policies#linking

8DUH1N11BX https://www.fda.gov/ForIndustry/DataStandards/SubstanceRegistrationSystem-UniqueIngredientIdentifierUNII/

23. FooDB LICENSE https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 66/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

FooDB is offered to the public as a freely available resource. Use and re-distribution of the data, in whole or in part, for commercial purposes requires explicit permission of the authors and explicit acknowledgment of the source material (FooDB) and the original publication. https://foodb.ca/about

L-Tryptophan https://foodb.ca/compounds/FDB002250

24. MassBank of North America (MoNA) LICENSE The content of the MoNA database is licensed under CC BY 4.0. https://mona.fiehnlab.ucdavis.edu/documentation/license

L-Tryptophan http://mona.fiehnlab.ucdavis.edu/spectra/browse?inchikey=QIVBCDIJIAJPQS-VIFPVBQESA-N

25. Nature Chemical Biology https://pubchem.ncbi.nlm.nih.gov/substance/24844224 https://pubchem.ncbi.nlm.nih.gov/substance/50086876 https://pubchem.ncbi.nlm.nih.gov/substance/81044574 https://pubchem.ncbi.nlm.nih.gov/substance/85147463 https://pubchem.ncbi.nlm.nih.gov/substance/386187140

26. Nature Chemistry https://pubchem.ncbi.nlm.nih.gov/substance/124384985

27. Protein Data Bank in Europe (PDBe) http://www.ebi.ac.uk/pdbe-srv/pdbechem/chemicalCompound/show/TRP

28. PubChem https://pubchem.ncbi.nlm.nih.gov

29. RCSB Protein Data Bank (RCSB PDB) LICENSE Data files contained in the PDB archive (ftp://ftp.wwpdb.org) are free of all copyright restrictions and made fully and freely available for both non-commercial and commercial use. Users of the data should attribute the original authors of that structural data. https://www.rcsb.org/pages/policies

http://www.rcsb.org/ligand/TRP

30. SpectraBase L-tryptophan https://spectrabase.com/spectrum/CWZ1qPp5RYt L-Tryptophan https://spectrabase.com/spectrum/3fL0hOG1boS Tryptophane https://spectrabase.com/spectrum/BgAkvrNkaag L-Tryptophan https://spectrabase.com/spectrum/CiwAts7BO1J L-Tryptophan https://spectrabase.com/spectrum/8dbHRajpbsm L-Tryptophan https://spectrabase.com/spectrum/D4XXGz8WgJD L-Tryptophan https://spectrabase.com/spectrum/B6sC84f9nom L-TRYPTOPHAN https://spectrabase.com/spectrum/5igUfe8kEci L-Tryptophan https://spectrabase.com/spectrum/85kIfNMWexq L-Tryptophan https://spectrabase.com/spectrum/3AAQHqIr1rm L-Tryptophan https://spectrabase.com/spectrum/AIdzN9TPhWJ L-Tryptophan https://spectrabase.com/spectrum/6lfLzgY6kEa L-Tryptophan https://spectrabase.com/spectrum/AMyC8yqhjm1 (2S)-2-Amino-3-(1H-2-indolyl)propionic acid (L-isotrytophan) https://spectrabase.com/spectrum/BsrajUtnG2y

31. Springer Nature https://pubchem.ncbi.nlm.nih.gov/substance/341139696

32. The Cambridge Structural Database https://www.ccdc.cam.ac.uk/structures/Search?Ccdcid=986568 https://www.ccdc.cam.ac.uk/structures/Search?Ccdcid=986569

33. Thieme Chemistry LICENSE The Thieme Chemistry contribution within PubChem is provided under a CC-BY-NC-ND 4.0 license, unless otherwise stated. https://creativecommons.org/licenses/by-nc-nd/4.0/

34. WHO Anatomical Therapeutic Chemical (ATC) Classification LICENSE Use of all or parts of the material requires reference to the WHO Collaborating Centre for Drug Statistics Methodology. Copying and distribution for commercial purposes is not allowed. Changing or manipulating the material is not allowed. https://www.whocc.no/copyright_disclaimer/

https://www.whocc.no/atc/ ATC Code https://www.whocc.no/atc_ddd_index/

35. Wiley https://pubchem.ncbi.nlm.nih.gov/substance/?source=wiley&sourceid=115570 https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 67/68 07.01.2021 Tryptophan | C11H12N2O2 - PubChem

36. MeSH Tryptophan https://www.ncbi.nlm.nih.gov/mesh/68014364 Antidepressive Agents, Second-Generation https://www.ncbi.nlm.nih.gov/mesh/68018687

37. Medical Subject Headings (MeSH) MeSH Tree http://www.nlm.nih.gov/mesh/meshhome.html

38. KEGG Compounds with biological roles http://www.genome.jp/kegg-bin/get_htext?br08001.keg Anatomical Therapeutic Chemical (ATC) classification http://www.genome.jp/kegg-bin/get_htext?br08303.keg Drugs listed in the Japanese Pharmacopoeia http://www.genome.jp/kegg-bin/get_htext?br08311.keg Risk category of Japanese OTC drugs http://www.genome.jp/kegg-bin/get_htext?br08312.keg Drug Classes http://www.genome.jp/kegg-bin/get_htext?br08330.keg

39. UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS) GHS Classification Tree http://www.unece.org/trans/danger/publi/ghs/ghs_welcome_e.html

40. ChEMBL Target Tree https://www.ebi.ac.uk/chembl/target/browser

41. IUPHAR/BPS Guide to PHARMACOLOGY Target Classification http://www.guidetopharmacology.org/

42. PATENTSCOPE (WIPO) SID 403033232 https://pubchem.ncbi.nlm.nih.gov/substance/403033232

https://pubchem.ncb.nlm.nh.gov/compound/Tryptophan#secton=Pathways 68/68