DOCSLIB.ORG

Continuous Production of Erythrulose Using Transketolase in a Membrane Reactor Jÿrgen Bongs, Doris Hahn, Ulrich Schšrken, Georg A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Continuous Production of Erythrulose Using Transketolase in a Membrane Reactor Jÿrgen Bongs, Doris Hahn, Ulrich Schšrken, Georg A Biotechnology Letters, Vol 19, No 3, March 1997, pp. 213–215 1 Continuous production of erythrulose using transketolase in a membrane reactor JŸrgen Bongs, Doris Hahn, Ulrich Schšrken, Georg A. Sprenger, 1 Udo Kragl* and Christian Wandrey Institut fŸr Biotechnologie, Forschungszentrum JŸlich GmbH, D-52425 JŸlich, Germany Transketolase can be used for synthesis of chiral intermediates and carbohydrates. However the enzyme is strongly deactivated by the educts. This deactivation depends on the reactor employed. An enzyme membrane reactor allows the continuous production of L-erythrulose with high conversion and stable operational points. A productivity (space- time yield) of 45 g LÐ1 dÐ1 was reached. 24 pts min base to base from Key words to line 1 of text 1 Introduction (10 mM), thiaminpyrophosphate (0.5 mM) and DTT (1 Transketolase (E.C. 2.2.1.1.) is used for the asymmetric mM). The substrate concentration of glycolaldehyde was synthesis of natural substances or their precursors 50 mM, the product concentration of L-erythrulose was such as carbohydrates (Drueckhammer et al., 1991), (+)- 50 mM, each compound dissolved in the liquid buffer exo-brevicomin (Myles et al., 1991), or fagomine system. Other reaction conditions were: pH = 7.0; (Effenberger and Null, 1992). In vivo transketolase cata- T = 25°C. lyses the reversible transfer of a two-carbon ketol moiety from a ketose to an aldose. When b-hydroxypyruvate Repetitive batch (HPA) is used as the donor substrate the reaction The reaction was performed in a commercially available becomes irreversible (Bolte et al., 1987) (Figure 1) even stirred ultrafiltration cell (Amicon) equipped with an 1 though there is a wide range of possible acceptor UF-membrane (Amicon) with a cut-off of 10 kDa. The substrates (aldehydes) (Demuynck et al., 1991; pH was measured and maintained at 7.0 using a pH Humphrey et al., 1995). Consequently, transketolase is controller (Methrom). The substrate concentrations a versatile tool for C-C-formation and for the insertion were: HPA (50 mM) and glycolaldehyde (50 mM). The of chirality in the scope of chemo-enzymatic synthesis. other reaction parameters are enumerated above. Recent papers have focused on the preparation of the Continuous stirred tank reactor (CSTR) products (Hobbs et al., 1993); but in regard to the large The continuous production was carried out in a 10 mL scale utilization of transketolase, the stability of the enzyme membrane reactor (EMR). Transketolase was enzyme and its deactivation play an important role. The separated from the product stream by means of the same 1 aim of this work was to identify limitations in the UF-membrane (Amicon) above. Enforced flow across the process in order to overcome unpleasant side reactions membrane and complete mixing in the reactor with a and to improve the performance of the reaction. magnetic stirrer ensured that the EMR behaved as a continuous stirred tank reactor. The substrate concen- Materials and methods trations at the inlet of the reactor were 50 mM. The Strain pH was adjusted to 7.0 with the buffer system above, Transketolase was purified to apparent homogeneity the temperature was 25°C. from recombinant E. coli K12 cells carrying the homol- ogous cloned tktA gene on a pUC-19 derived plasmid. Analytical methods The concentrations of the substrates and the product 1 Enzyme activity assay were monitored by HPLC (Sykam) using a cation- The deactivation of transketolase was monitored by exchange column HPX-87H (BIORAD), eluent 6 mM photometric assay (Sprenger et al., 1995). The buffer sulphuric acid, 65°C, 0.6 mL/min, photometric detec- system contains glycyl-glycine (50 mM), MgCl2 tion at 195 nm. © 1997 Chapman & Hall Biotechnology Letters · Vol 19 · No 3 · 1997 213 J. Bongs et al. 1 1 Figure 1 Reaction scheme of a transketolase-catalyzed interconversion. Results and discussion Figure 3 Concentration change in a batch reactor The source of transketolase used in this work were compared to a continuous stirred tank reactor (CSTR). recombinant E. coli cells (Sprenger et al., 1995). After fermentation in a 200 L scale the purification of the high conversion the substrate concentration is constant crude extract provided up to 720 000 Units. at a low level. Consequently the rate of deactivation 1 should be very small. The enzyme is retained by an The formation of L-erythrulose by transketolase- ultrafiltration (UF)-membrane. Only the product and catalyzed interconversion of HPA and glycolaldehyde the remaining unreacted substrate can pass the was investigated; in the course of the reaction L-erythru- membrane. lose is formed. The rate of deactivation for transketo- lase caused by the reactive a-hydroxy aldehyde is much The experimental verification of this strategy is shown higher than by the synthesized product (Figure 2). in Figures 4 and 5. In Figure 4 the reaction is performed as repetitive batch. After complete conversion (2 h) The typical course of the substrate and product concen- the enzyme is filtered by means of a stirred Amicon® trations in a batch and a continuous process are UF-cell (Kragl et al., 1993). Due to the repeated high 1 compared in Figure 3. In case of the batch process in substrate concentration the strong transketolase-deacti- the beginning of the reaction the substrate concentra- vation extends the reaction time. Therefore in the last tion is high, yielding in a high transketolase-deactiva- batch, 7 h instead of 2 h like in the first batch are tion. Contrary to this reactor type in an enzyme required to reach complete conversion. The overall membrane reactor (EMR), which operates as a contin- space-time yield for L-erythrulose is 28 g L–1 d–1 and 1 uously stirred tank reactor with constant discharge, at the half-life of transketolase is only t ⁄2 = 5.6 h. 1 1 Figure 2 Deactivation of transketolase in dependence of Figure 5 Continuously operated reactor: Conversion of buffer, substrate and product. HPA and glycolaldehyde to L-erythrulose. 214 Biotechnology Letters · Vol 19 · No 3 · 1997 Continuous production of erythrulose using transketolase in a membrane reactor 1 1 1 Figure 4 Repetitive batch: Conversion of HPA and glycolaldehyde to L-erythrulose and decrease of activity of transketolase. Contrary to this batch operation a stable conversion of Acknowledgement 1 nearly 90% is reached in a continuously operated reactor Part of this work was financed by Deutsche for a period of more than 20 h (residence time t = 2 h), Forschungsgemeinschaft: SFB 380 ‘Asymmetric Synthesis since the deactivation of transketolase is minimal with Chemical and Biological Methods’. (Figure 5). Under these conditions the space-time yield for L-erythrulose is 45 g L–1 d–1 and the half-life of References 1 Bolte, J., Demuynck, C., Samaki, H. (1987) Tetrahedron Lett. 28, transketolase is drastically increased up to t 2= 106 h. ⁄ 5525–5528. After a reduction of the residence time to 0.25 h Dalmas, V., Demuynck, C. (1993) Tetrahedron: Asymm. 4, the conversion decreases to 38%. Accordingly the 2383–2388. substrate concentration raises and no steady-state condi- Demuynck, C., Bolte, J., Hecquet, L., Dalmas, V. (1991) tions are reached anymore due to the strong continual Tetrahedron Lett. 32, 5085–5088. 1 deactivation of transketolase. After increasing the resi- Drueckhammer, D.G., Hennen, W.J., Pederson, R.L., Barbas III, C.F., Gautheron, C.M., Krach, T., Wong, C.-H. (1991) dence time again a constant conversion is reached but Synthesis, 499–525. now at a lower level caused by the deactivated trans- Effenberger, F., Null, V. (1992) Liebigs Ann. Chem., 1211–1212. ketolase. Hobbs, G.R., Lilly, M.D., Turner, N.J., Ward, J.M., Willets, A.J., Woodley, J.M. (1993) J. Chem. Soc. Perkin Trans. 1, 165–166. Humphrey, A.J., Turner, N.J., McCague, R., Taylor, S.J.C. However, the described process for the use of tran- (1995) J. Chem. Soc.,Chem. Commun. 2475–2476. sketolase provides an efficient tool for the continuous Kragl, U., Gödde, A., Wandrey, C., Kinzy, W., Cappon, J.J., large-scale production of L-erythrulose. Further studies Lugtenburg, J. (1993) Tetrahedron: Asymm. 4 (6), 1193–1202. Myles, D.C., Andrulis III, P.J., Whitesides, G.M. (1991) on various aldehydes ought to open a wide range Tetrahedron Lett. 32, 4835–4838. 1 of other products employing the presented reactor Sprenger, G.A., Schörken, U., Sprenger, G., Sahm, H. (1995) optimization. Eur. J. Biochem. 230, 525–532. Received as Revised 16 January 1997 Biotechnology Letters · Vol 19 · No 3 · 1997 215.
Load more

Recommended publications
  • 48 3-1-4. Reactions Using Mutant FSA A129S Another Mutant Enzyme
    Results _ 3-1-4. Reactions using mutant FSA A129S Another mutant enzyme, A129S, which has serine at 129th residue instead of alanine (Fig.3-11a), has high potential to catalyze the reactions using DHA as a donor substrate. Virtually, the kcat/Km value for DHA is more than 12 fold of that of WT (Schürmann, 2001). This implies that larger amounts of products can be acquired with A129S than with WT, or unfavorable reactions with WT may be accomplished with the mutant enzyme. Firstly, FSA A129S was produced in DH5α with pUC18 plasmid vector and purified with same method as WT was done (Fig.3-11b, Table 3-8). This mutant enzyme was overexpressed well and a strong band corresponding to FSA was seen on SDS-PAGE gel (as 10~15% of total protein in crude extract). In addition, this mutant enzyme held the stability against high temperature. Thus, a heat treatment step was part of the purification protocol. However, protein solution obtained from hydroxyapatite column of the final purification step showed still a few extra protein bands on SDS-PAGE gel (Fig.3-11b). Although it contained those extra proteins, the purity appeared to be more than 90% on the gel and the specific activity was quite high enough to assay the catalytic ability of the enzyme for several substrates. Indeed, even crude extract showed higher specific activity than purified WT had (Table 3-8). Three reactions (scheme 3-1) were probed to assay catalytic ability of both FSA WT and A129S. Dihydroxyacetone (DHA) or hydroxyacetone (HA) were used as donor substrates, and formaldehyde or glycolaldehyde as acceptor.
    [Show full text]
  • United States Patent Office
    - 2,926,180 United States Patent Office Patented Feb. 23, 1960 2 cycloalkyl, etc. These substituents R and R' may also be substituted with various groupings such as carboxyl 2,926,180 groups, sulfo groups, halogen atoms, etc. Examples of CONDENSATION OF AROMATIC KETONES WITH compounds which are included within the scope of this CARBOHYDRATES AND RELATED MATER ALS 5 general formula are acetophenone, propiophenone, benzo Carl B. Linn, Riverside, Ill., assignor, by mesne assign phenone, acetomesitylene, phenylglyoxal, benzylaceto ments, to Universal Oil Products Company, Des phenone, dypnone, dibenzoylmethane, benzopinacolone, Plaines, Ill., a corporation of Delaware dimethylaminobenzophenone, acetonaphthalene, benzoyl No Drawing. Application June 18, 1957 naphthalene, acetonaphthacene, benzoylnaphthacene, ben 10 zil, benzilacetophenone, ortho-hydroxyacetophenone, para Serial No. 666,489 hydroxyacetophenone, ortho - hydroxy-para - methoxy 5 Claims. (C. 260-345.9) acetophenone, para-hydroxy-meta-methoxyacetophenone, zingerone, etc. This application is a continuation-in-part of my co Carbohydrates which are condensed with aromatic pending application Serial No. 401,068, filed December 5 ketones to form a compound selected from the group 29, 1953, now Patent No. 2,798,079. consisting of an acylaryl-desoxy-alditol and an acylaryl This invention relates to a process for interacting aro desoxy-ketitol include simple sugars, their desoxy- and matic ketones with carbohydrates and materials closely omega-carboxy derivatives, compound sugars or oligo related to carbohydrates. The process relates more par saccharides, and polysaccharides. ticularly to the condensation of simple sugars, their 20 Simple sugars include dioses, trioses, tetroses, pentoses, desoxy- and their omega-carboxy derivatives, compound hexoses, heptoses, octoses, nonoses, and decoses. Com sugars or oligosaccharides, and polysaccharides with aro pound sugars include disaccharides, trisaccharides, and matic ketones in the presence of a hydrogen fluoride tetrasaccharides.
    [Show full text]
  • Assessment of DHA in Self-Tanning Creams Applied in Spray Booths
    Assessment of DHA in self-tanning creams applied in spray booths Lena Höglund MSc. DTC (Danish Toxicology Centre): Betty Bügel Mogensen Rossana Bossi Marianne Glasius National Environmental Research Institute of Denmark Survey of Chemical Substances in Consumer Products, No. 72 2006 The Danish Environmental Protection Agency will, when opportunity offers, publish reports and contributions relating to environmental research and development projects financed via the Danish EPA. Please note that publication does not signify that the contents of the reports necessarily reflect the views of the Danish EPA. The reports are, however, published because the Danish EPA finds that the studies represent a valuable contribution to the debate on environmental policy in Denmark. Contents SUMMARY AND CONCLUSIONS 5 1 INTRODUCTION 7 2 OBJECTIVES 10 3 TECHNIQUES 12 3.1 DESCRIPTION OF TECHNIQUES 12 3.1.1 Manual turbine spray 12 3.1.2 Third-generation booths (closed booths) 13 3.1.3 Fourth-generation booths (open booths) 15 3.2 SAFETY INSTRUCTIONS 16 3.2.1 General remarks on enterprises' safety instructions 16 3.2.2 Safety instructions from the authorities 16 3.2.3 Advice for customers from personnel 16 4 SUBSTANCES CONTAINED IN PRODUCTS 20 5 HEALTH ASSESSMENT 22 5.1 TOXOCOLOGICAL PROFILE OF DIHYDROXYACETONE (DHA) (CAS NO. 96-26-4) 22 5.2 BRIEF HEALTH ASSESSMENT OF ETHOXYDIGLYCOL (CAS NO. 111-90-0) 26 5.3 BRIEF HEALTH ASSESSMENT OF PHENOXYETHANOL (CAS NO.122-99-6) 27 5.4 BRIEF HEALTH ASSESSMENT OF GLYCERINE (CAS NO. 56-81-5) 27 5.5 BRIEF HEALTH ASSESSMENT OF POLYSORBATES AND SORBITAN ESTERS 27 5.6 BRIEF HEALTH ASSESSMENT OF ERYTHRULOSE (CAS NO.
    [Show full text]
  • Unit 1: Carbohydrates Structure and Biological Importance: Monosaccharides, Disaccharides, Polysaccharides and Glycoconjugates
    CBCS 3rd Semester Core Course VII Paper: Fundamentals of Biochemistry Unit 1: Carbohydrates Structure and Biological importance: Monosaccharides, Disaccharides, Polysaccharides and Glycoconjugates By- Dr. Luna Phukan Definition The carbohydrates are a group of naturally occurring carbonyl compounds (aldehydes or ketones) that also contain several hydroxyl groups. It may also include their derivatives which produce such compounds on hydrolysis. They are the most abundant organic molecules in nature and also referred to as “saccharides”. The carbohydrates which are soluble in water and sweet in taste are called as “sugars”. Structure of Carbohydrates Carbohydrates consist of carbon, hydrogen, and oxygen. The general empirical structure for carbohydrates is (CH2O)n. They are organic compounds organized in the form of aldehydes or ketones with multiple hydroxyl groups coming off the carbon chain. The building blocks of all carbohydrates are simple sugars called monosaccharides. A monosaccharide can be a polyhydroxy aldehyde (aldose) or a polyhydroxy ketone (ketose) The carbohydrates can be structurally represented in any of the three forms: 1. Open chain structure. 2. Hemi-acetal structure. 3. Haworth structure. Open chain structure – It is the long straight-chain form of carbohydrates. Hemi-acetal structure – Here the 1st carbon of the glucose condenses with the -OH group of the 5th carbon to form a ring structure. Haworth structure – It is the presence of the pyranose ring structure Classification of Carbohydrates Monosaccharides The simple carbohydrates include single sugars (monosaccharides) and polymers, oligosaccharides, and polysaccharides. Simplest group of carbohydrates and often called simple sugars since they cannot be further hydrolyzed. Colorless, crystalline solid which are soluble in water and insoluble in a non-polar solvent.
    [Show full text]
  • Erythritol As Sweetener—Wherefrom and Whereto?
    Applied Microbiology and Biotechnology (2018) 102:587–595 https://doi.org/10.1007/s00253-017-8654-1 MINI-REVIEW Erythritol as sweetener—wherefrom and whereto? K. Regnat1 & R. L. Mach1 & A. R. Mach-Aigner1 Received: 1 September 2017 /Revised: 12 November 2017 /Accepted: 13 November 2017 /Published online: 1 December 2017 # The Author(s) 2017. This article is an open access publication Abstract Erythritol is a naturally abundant sweetener gaining more and more importance especially within the food industry. It is widely used as sweetener in calorie-reduced food, candies, or bakery products. In research focusing on sugar alternatives, erythritol is a key issue due to its, compared to other polyols, challenging production. It cannot be chemically synthesized in a commercially worthwhile way resulting in a switch to biotechnological production. In this area, research efforts have been made to improve concentration, productivity, and yield. This mini review will give an overview on the attempts to improve erythritol production as well as their development over time. Keywords Erythritol . Sugar alcohols . Polyols . Sweetener . Sugar . Sugar alternatives Introduction the range of optimization parameters. The other research di- rection focused on metabolic pathway engineering or genetic Because of today’s lifestyle, the number of people suffering engineering to improve yield and productivity as well as to from diabetes mellitus and obesity is increasing. The desire of allow the use of inexpensive and abundant substrates. This the customers to regain their health created a whole market of review will present the history of erythritol production- non-sugar and non-caloric or non-nutrient foods. An impor- related research from a more commercial viewpoint moving tant part of this market is the production of sugar alcohols, the towards sustainability and fundamental research.
    [Show full text]
  • Ii- Carbohydrates of Biological Importance
    Carbohydrates of Biological Importance 9 II- CARBOHYDRATES OF BIOLOGICAL IMPORTANCE ILOs: By the end of the course, the student should be able to: 1. Define carbohydrates and list their classification. 2. Recognize the structure and functions of monosaccharides. 3. Identify the various chemical and physical properties that distinguish monosaccharides. 4. List the important monosaccharides and their derivatives and point out their importance. 5. List the important disaccharides, recognize their structure and mention their importance. 6. Define glycosides and mention biologically important examples. 7. State examples of homopolysaccharides and describe their structure and functions. 8. Classify glycosaminoglycans, mention their constituents and their biological importance. 9. Define proteoglycans and point out their functions. 10. Differentiate between glycoproteins and proteoglycans. CONTENTS: I. Chemical Nature of Carbohydrates II. Biomedical importance of Carbohydrates III. Monosaccharides - Classification - Forms of Isomerism of monosaccharides. - Importance of monosaccharides. - Monosaccharides derivatives. IV. Disaccharides - Reducing disaccharides. - Non- Reducing disaccharides V. Oligosaccarides. VI. Polysaccarides - Homopolysaccharides - Heteropolysaccharides - Carbohydrates of Biological Importance 10 CARBOHYDRATES OF BIOLOGICAL IMPORTANCE Chemical Nature of Carbohydrates Carbohydrates are polyhydroxyalcohols with an aldehyde or keto group. They are represented with general formulae Cn(H2O)n and hence called hydrates of carbons.
    [Show full text]
  • Monosaccharides
    UNIT 5 MONOSACCHARIDES Structure 5.1 Introduction 5.4 Biologically Important Sugar Derivatives Expected Learning Outcomes Sugar Acids 5.2 Overview of Carbohydrates Sugar Alcohols Amino Sugars 5.3 Monosaccharides Deoxy Sugars Linear Structure Sugar Esters Ring Structure Glycosides Conformations 5.5 Summary Stereoisomers 5.6 Terminal Questions Optical Properties 5.7 Answers 5.8 Further Readings 5.1 INTRODUCTION Carbohydrates constitute the most abundant organic molecules found in nature and are widely distributed in all living organisms. These are synthesized in nature by green plants, algae and some bacteria by photosynthesis. They also form major part of our diet and provide us energy required for the life sustaining activities such as growth, metabolism and reproduction. At microscopic level, these constitute the structural components of the cell such as cell membrane and cell wall. In this unit, we shall begin with general overview of the chemical nature of carbohydrates and their classification. The unit focuses mainly on the simplest carbohydrates known as monosaccharides. We shall learn about the chemical structures of different monosaccharides and how to draw them. We shall also discuss their stereochemistry in detail which would help to understand how change in orientation of same substituents results in different molecules with same chemical formula but different properties. We shall also discuss about some of the chemical reactions of monosaccharides resulting in 77 formation of important derivatives and their biological importance.
    [Show full text]
  • Glycosidic Bond Or O-Glycosidic Bond, at Need
    Seminar 4 Carbohydrates Definition Saccharides (glycids) are polyhydroxyaldehydes, polyhydroxyketones, or substances that give such compounds on hydrolysis 3 Classification Basal units Give monosaccharides when hydrolyzed MONOSACCHARIDES OLIGOSACCHARIDES POLYSACCHARIDES polyhydroxyaldehydes polyhydroxyketones 2 – 10 basal units polymeric GLYCOSES (sugars) GLYCANS water-soluble, sweet taste Don't use the historical misleading term carbohydrates, please. It was primarily derived from the empirical formula Cn(H2O)n and currently is taken as incorrect, not recommended in the IUPAC nomenclature (even though it can be found in numerous textbooks till now) 4 Saccharides • occur widely in the nature, present in all types of cells – the major nutrient for heterotrophs – energy stores (glycogen, starch) – components of structural materials (glycosaminoglycans) – parts of important molecules (nucleic acids, nucleotides, glycoproteins, glycolipids) – signalling function (recognition of molecules and cells, antigenic determinants) 5 Monosaccharides are simple sugars that cannot be hydrolyzed to simpler compounds Aldoses Ketoses Simple derivatives (polyhydroxyaldehydes) (polyhydroxyketones) modified monosaccharides are further classified according to the deoxysugars number of carbon atoms in their chains: amino sugars glyceraldehyde (a triose) dihydroxyacetone uronic acids tetroses tetruloses other simple derivatives pentoses pentuloses alditols hexoses hexuloses glyconic acids heptoses … heptuloses … glycaric acids Trivial names for stereoisomers glucose
    [Show full text]
  • Metabolic Engineering 2017.Pdf
    Metabolic Engineering 42 (2017) 19–24 Contents lists available at ScienceDirect Metabolic Engineering journal homepage: www.elsevier.com/locate/meteng Enhancing erythritol productivity in Yarrowia lipolytica using metabolic MARK engineering Frédéric Carlya, Marie Vandermiesb, Samuel Telekb, Sébastien Steelsb, Stéphane Thomasc, ⁎ Jean-Marc Nicaudc, Patrick Fickersb, a Unité de Biotechnologies et Bioprocédés, Université Libre de Bruxelles, Belgium b Microbial Processes and Interactions, TERRA Teaching and Research Centre, University of Liège - Gembloux Agro-Bio Tech, Belgium c Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France ARTICLE INFO ABSTRACT Keywords: Erythritol (1,2,3,4-butanetetrol) is a four-carbon sugar alcohol with sweetening properties that is used by the Yarrowia lipolytica agrofood industry as a food additive. In this study, we demonstrated that metabolic engineering can be used to Erythritol improve the production of erythritol from glycerol in the yeast Yarrowia lipolytica. The best results were obtained Metabolic engineering using a mutant that overexpressed GUT1 and TKL1, which encode a glycerol kinase and a transketolase, Glycerol kinase respectively, and in which EYK1, which encodes erythrulose kinase, was disrupted; the latter enzyme is involved Transketolase in an early step of erythritol catabolism. In this strain, erythritol productivity was 75% higher than in the wild Erythrulose kinase type; furthermore, the culturing time needed to achieve maximum concentration was reduced by 40%. An additional advantage is that the strain was unable to consume the erythritol it had created, further increasing the process's efficiency. The erythritol productivity values we obtained here are among the highest reported thus far. 1. Introduction as mannitol, and organic acids which renders the downstream proces- sing more challenging.
    [Show full text]
  • CH 460 Dr. Muccio Worksheet 4 1. What Is the Difference Between An
    CH 460 Dr. Muccio Worksheet 4 1. What is the difference between an aldose and a ketose? 2. What is the oxidation number of the carbon on the following 3 groups? 3. Circle the carbons in the figure below that are chiral. How many isomers does this molecule have? 4. What is the difference between an epimer and an enantiomer? 5. How is the Fisher projection of D-glucose converted to L-glucose? 6. The chemical formula of a tetrose monosaccharide is _____. a. C6H12O6 b.C4H10O4 c.C6H10O4 d.C4H8O4 e.None 7. Match the carbohydrates to their descriptions on the left. i. D-Glyceraldehyde _____ A. C-2 Epimer of Glucose ii. D-Threose _____ B. C-2 Epimer of Threose iii. D-Ribose _____ C. Pentose with D,D,D stereochem iv. D-Mannose _____ D. Triose v. D-Galactose _____ E. Hexose with DLDD stereochem vi. D-Erythrose _____ F. C-3 Epimer of Ribose vii. D-Xylose _____ G. C-4 Epimer of Glucose viii. D-Glucose _____ H. C-2 Epimer of Erythrose ix. D-Arabinose _____ I. C-2 Epimer of Ribose x. D-Fructose _____ J. Ketose of Letter D xi. D-Xylulose _____ K. Ketose of Letter F xii. D-Erythrulose _____ L. Enantiomer of Letter A xiii. Dihydroxyacetone ____ M. Ketose of Letter B xiv. D-Ribulose _____ N. Ketose of Letter E xv. L-Mannose _____ O. Ketose of Letter C CH 460 Dr. Muccio Worksheet 4 8. In the conversion of aldoses to their ketoses, the _____ carbon loses its stererochemistry.
    [Show full text]
  • Chemical and Functional Properties of Food Saccharides
    Chemical and Functional Properties of Food Saccharides © 2004 by CRC Press LLC Chemical and Functional Properties of Food Components Series SERIES EDITOR Zdzislaw E. Sikorski Chemical and Functional Properties of Food Proteins Edited by Zdzislaw E. Sikorski Chemical and Functional Properties of Food Components, Second Edition Edited by Zdzislaw E. Sikorski Chemical and Functional Properties of Food Lipids Edited by Zdzislaw E. Sikorski and Anna Kolakowska Chemical and Functional Properties of Food Saccharides Edited by Piotr Tomasik © 2004 by CRC Press LLC Chemical and Functional Properties of Food Saccharides EDITED BY Piotr Tomasik CRC PRESS Boca Raton London New York Washington, D.C. © 2004 by CRC Press LLC 1486_C00.fm Page 4 Monday, September 8, 2003 8:01 AM Library of Congress Cataloging-in-Publication Data Chemical and functional properites of food saccharides / edited by Piotr Tomasik. p. cm. — (Chemical and functional properites of food components series ; 5) Includes bibliographical references and index. ISBN 0-8493-1486-0 (alk. paper) 1. Sweeteners. I. Tomasik, Piotr. II. Title. III. Series. TP421.C44 2003 664—dc21 2003053186 This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage or retrieval system, without prior permission in writing from the publisher.
    [Show full text]
  • University Microfilms, Inc., Ann Arbor, Michigan ILLUS TRATIONS— (Continued) Figure Page
    This dissertation has been 64—6920 microfilmed exactly as received JORDAN, John Maxwell, 1938- STUDIES ON METABOLISM IN PENICILLIUM CHARLESII; SOME RELATIONSHIPS BETWEEN DICARBOXYLIC ACID METABOLISM AND PRO­ DUCTION OF GALACTOCAROLOSE. The Ohio State University, Ph.D., 1963 Chemistry, biological University Microfilms, Inc., Ann Arbor, Michigan ILLUS TRATIONS— (Continued) Figure Page 12 Variation with time of carbohydrate concentration of systems containing various concentrations of diammonium dihydroxymaleate . ................ 88 13 Atypical behavior of system containing high level of medium n i t r o g e n ......................... 99 14 Changes in hydrogen ion concentration and carbo­ hydrate concentration of growth medium of the RTg and RT^ series ...•••• ............. 101 15 Changes in hydrogen ion and carbohydrate concen­ tration of the growth medium for the DHM_ and DHM., series ........... ......... • • 104 16 Changes in hydrogen ion and carbohydrate concen­ tration of the growth medium for the Funig and Fum^ series .................... ........ 106 17 Changes in hydrogen ion and carbohydrate concen­ tration of the growth medium for the Mal_ and Mal^ series 110 32 18 Distribution of P -labeled components of a perchloric acid extract of P. charlesii exposed 4.5 days to orthophosphate-P^^ • • • T ..... 126 32 19 Distribution of P -labeled components of a perchloric acid extract of P. charlesii exposed 9 days to orthophosphate-P^............. 129 32 20 Distribution of P -labeled components of a . perchloric acid extract of P. charlesii exposed 13.5 days to orthophosphate-P^ . I I ~ ..... 133 32 21 Distribution of P -labeled components of a perchloric acid extract of P. charlesii exposed l8.0 days to orthophosphate-P^^T • • • • • 136 22 Distribution of P^-labeled and U.V.-light ab­ sorbing components of perchloric acid extract of P.
    [Show full text]