DOCSLIB.ORG

Diethyl Pyrocarbonate at Ph6.5, When 0.58+0.1Residue Of

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Diethyl Pyrocarbonate at Ph6.5, When 0.58+0.1Residue Of Aiochem. J. (1974) 139, 797-800 797 Printed in Great Britain Histidine Residues and the Enzyme Activity of Pig Heart Supernatant Malate Dehydrogenase By J. JOHN HOLBROOK, A. LODOLA and NICHOLAS P. ILLSLEY Department ofBiochemistry, University ofBristol, Bristol BS8 1TD, U.K. (Received 25 February 1974) 1. Supernatant pig heart malate dehydrogenase is completely inhibited by reaction with diethyl pyrocarbonate at pH6.5, when 0.58+0.1 residue of ethoxycarbonylhistidine is formed per NADH-binding site. 2. Oxaloacetate and hydroxymalonate protect the en- zyme from inhibition in the absence of coenzyme. 3. Limited ethoxycarbonylation does not alter the binding of NADH to the enzyme but prevents the enzyme-NADH complex from interacting with hydroxymalonate in a ternary complex. Supematant malate dehydrogenase and lactate de- and the crystals were dissolved in 20mM-H3P04 hydrogenase have very similar tertiary structures adjusted to pH6.5 with 5M-NaOH and then filtered (Hill et al., 1972; Adams et al., 1972). Histidine-195 through a column of Sephadex G-50 equilibrated in plays a central role in the activity of lactate dehydro- the same buffer. If (NH4)2SO4 was not completely genase as the acceptor and donor of the proton in- removed it competed effectively for the diethyl pyro- volved in the reaction (Holbrook & Gutfreund, 1973). carbonate. This latter reagent was obtained from A proton is also a reactant for malate dehydrogenase, Sigma (London) Chemical Co., Kingston-on- and the work reported here is an attempt to discover Thames, U.K., and the batch used in these experi- if this enzyme also has a histidine residue with the ments was 2.6M when assayed as described by same function as histidine-195 of lactate dehydro- Holbrook & Ingram (1973). genase. Anderton & Rabin (1970) found that a histi- Preliminary experiments established that enzyme dine residue was involved in the activity of the mito- was most rapidly inhibited in a buffer prepared by chondrial malate dehydrogenase, although it is not adjusting a solution of 20mM-H3PO4 with 5M-NaOH known ifthis form ofmalate dehydrogenase is a struc- to pH6.5. This buffer was used for all theexperiments tural homologue of lactate dehydrogenase. reported in this paper. The rate of inhibition was half The method ofGerding & Wolfe (1969) was used to itsmaximumvalue at pH6 and 7.5. The enzyme could prepare the supernatant enzyme from pig heart. The be protected from inhibition by diethyl pyrocarbon- negative absorptions (steps 4-7) were not necessary. ate if substrates and coenzymes were present in the In our hands the hydroxyapatite column chromato- incubation mixture. For example, the rate of loss of graphy did not reproducibly give a purification and enzyme activity (kobl. = 2min-'; samples assayed was omitted. Enzyme activity was expressed as units every i5s) when 7p/M-enzyme (calculated from a rela- of umol of NADH produced/min in an incubation tive subunit mass of 35000) was incubated with mixture containing at 25°C 5mM-NAD+, O.1M-L- 0.78mM-inhibitor was decreased 10-fold by the inclu- malate and 0.1M-glycine adjusted to pH 10 with SM- sion of either 3mM-oxaloacetate or 25,UM-NADH in NaOH. Protein was determined from absorbance the incubation mixture. In another experiment with measurements at 280nm by using E1',1 = 9.3 given by 284uM-enzyme and 0.5mM-inhibitor the rate of inhibi- Gerding & Wolfe (1969). The specific enzyme activity tion was decreased 10-fold by 3.3mM-hydroxy- of our preparations was 77 units/mg; this is only 70% malonate or 0.4mM-NADH and no inhibition was of the 108 units/mg reported by Gerding & Wolfe detected over 20min if the hydroxymalonate and (1969) for the pure enzyme. The presence of impurity NADH were both present. Oxaloacetate did not re- could also be deduced from a determination of the act with the inhibitor. There is as yet no definitive NADH-binding capacity of the preparation by using steady-state kinetic investigation of the mechanism of the supernatant enzyme. The form of the initial the continuous micro-fluorimetric titration as re- velocity equations is consistent with a sequential Bi Bi ported by Holbrook & Wolfe (1972). Only 1.4mol of mechanism (A. Lodola, unpublished work), but it is NADH was bound per mol ofprotein, assuming that not known whether there is a compulsory, preferred the protein molecule consists of two subunits of or random order of addition of substrate and co- mol.wt. 35000. Before the experiments reported here enzyme. The above results suggest that a preferred or the crystalline enzyme suspension was centrifuged random order should be considered, although the Vol. 139 798 J. J. HOLBROOK, A. LODOLA AND N. P. ILLSLEY protection by oxaloacetate in the absence of NADH measured against that ofan uninhibited control. With does not necessarily mean that this substrate binds at greater degrees of inhibition a negative absorbance the active site. peak at 280am appeared (ethoxycarbonyltyrosine; Inhibition after reaction with diethyl pyrocarbon- Muhlrad et al., 1967). The rate of appearance of ate is due to the modification of histidine residues. ethoxycarbonylhistidine was approx. 40M1-s-1 at Although the inhibitor will react with other side pH6.5, and this is smilar to the rate of reaction of chains it was possible to reactivate the inhibited free imidazoles at the same pH (Holbrook & Ingram, enzyme with hydroxylamine. For example 4uM- 1973). The rate of reaction was not quite fast enough enzyme was 98% inhibited after incubation with the for it to be possible to add 1 equivalent of inhibitor inhibitor (2.6mM) for 10min and then diluted into to 1 equivalent of enzyme and observe 100% 0.7M-hydroxylamine hydrochloride, which had been inhibition with the formation of 1 equivalent of adjusted to pH6.5 with SM-NaOH. When assayed ethoxycarbonylhistidine. The closest that this ideal after 10min the enzyme activity was 100±5% of that has been approached is in experiments similar to that of an untreated control. Hydroxylamine regenerates shown in Fig. 1. In that case 86gM-inhibitor reacted histidine fromethoxycarbonylhistidine, but iswithout with 72,gM-active enzyme to yield 36gM-ethoxycarb- effect on the ethoxycarbonyl derivatives of tyrosine onylhistidine and 68% inhibition after 18min. Thus and lysine (Melchior & Fahrney, 1970). Cysteine there is sufficient inhibitor unaccounted for to allow residues are not essential for the activity of this the reaction of up to 0.5mol of another amino acid enzyme (Devenyi etal., 1966). When inhibited enzyme side chain/mol of NADH-binding sites. Such a was freed from excess ofinhibitor byfiltration through calculation is the worst case and does not take into a column of Sephadex G-50 the enzyme activity of account the loss of inhibitor by hydrolysis during the the protein peak slowly reappeared. The initial rate of 18min incubation. regain of activity was approx. 2%/h. This is much The results described in detail in the legend to Fig. 1 slower than with lactate dehydrogenase or glutamate show that a sample of enzyme (3.6mg/ml) containing dehydrogenase (Holbrook & Ingram, 1973; Wallis & 72gM-NADHrbinding sites is completely inhibited Holbrook, 1973). by the reaction of0.58+±0.1 histidine residue/NADH- The fonnation of ethoxycarbonylhistidine in an binding site. It seems unlikely that this unusual ratio enzyme can be monitored from the absorbance peak arises from the use of only 70 %-active enzyme, since at 240nm. In samples of enzyme that had not been the results are referred to NADH-binding sites. The more than 90% inhibited this was the only absorbance reactivation of the enzyme in hydroxylamine indi- peak visible in a spectrum of the inhibited enzyme cates that it is the histidine modification that causes I100 0 Time (min) [Eth.oxycarbonylhistidinelI(#M) Fig. 1. Inkibition ofsupernatant malate dehydrogenase by ethoxycarbonylation ofhitidine residues in the enzyme Fig. 1(a) is a record ofthe increase in absorbance at 250nm in a solution containing enzyme (3.6mg/ml, 70% active, 72pM in sites that can bind NADH) monitored on a double-bearn spectrophotometer with a recorder output sensitivity of 0.15 absorbance unit full scale during reaction with 86pM-diethyl pyrocarbonatp at pH6.5. After 19min the inhibitor concentra- tion was increased to 133 gM. During this and similar reactions samples of the incubation mixture were assayed for enzyme activity, and Fig. l(b) shows the relation between the residual enzyme activity and the concentration of ethoxycarbonyl- histidine formed on the enzyme: 1 mm-ethoxycarbonylhistidine has an absorbance of 1.9 in a 1cm light-path at 250nm(Hol- brook & Ingran, 1973). The two broken lines enclose the results and indicate that t-he enzyme is inhibited by formation of 0.58±O.Imol -of ethoxycarbonylhistidine/mol of N-AD-binding sites. 1974 SHORT COMMUNICATIONS 799 (a) (b) - 6 5o48 4U4c a~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 0~~~~~~~~~~~~~~~ 0~~~~~~~~~~~~~~~~~ C) ~ [AH A)Ihbtonb ity yoabnt (%) a)~~~~~~~~~~~~~~~~ 0 a) AD- (m Ihbtonb ithlprcabnt Fig. 2. Nucleotide bindingbyethoxycarbonylatedmalatedehydrogenase Samples of enzyme (l65,UM in NADH-binding sites) were incubated with concentrations of diethyl pyrocarbonate between 130,M and 2.6mM for 5min. At exactly the same moment one portion ofthe incubation mixture was diluted 1:100 (v/v) and immediately assayed, while another portion was diluted 35-fold into lOmM-hydroxymalonate in 20mM-H3PO4 (which had been adjusted to pH6.5 with 5M-NaOH) and was titrated micro-fluorimetrically with NADH. The traces in Fig. 2(a) show the increases in NADH fluorescence (excited at 320nm, emission at about 430nm via a Kodak Wratten no. 98 filter) after subtraction of the fluorescence of NADH added to a solution without enzyme. The apparatus was described by Holbrook (1972) and the application to malate dehydrogenase by Holbrook & Wolfe (1972).
Load more

Recommended publications
  • Flammable Liquids and Solids Chemical Class Standard Operating Procedure
    1 Flammable Liquids and Solids Chemical Class Standard Operating Procedure Flammable Liquids and Solids H224 H225 H226 H227 H228 This SOP is not a substitute for hands-on training. Print a copy and insert into your laboratory SOP binder. Department: Chemistry Date SOP was written: Thursday, July 1, 2021 Date SOP was approved by PI/lab supervisor: Thursday, July 1, 2021 Name: F. Fischer Principal Investigator: Signature: ______________________________ Name: Matthew Rollings Internal Lab Safety Coordinator or Lab Manager: Lab Phone: 510.301.1058 Office Phone: 510.643.7205 Name: Felix Fischer Emergency Contact: Phone Number: 510.643.7205 Tan Hall 674, 675, 676, 679, 680, 683, 684 Location(s) covered by this SOP: Hildebrand Hall: D61, D32 1. Purpose This SOP covers the precautions and safe handling procedures for the use of Flammable Liquids and Solids. For a list of Flammable Liquids and Solids covered by this SOP and their use(s), see “List of Chemicals”. Procedures described in Section 12 apply to all materials covered in this SOP. A change to the “List of Chemicals” does not constitute a change in the SOP requiring review or retraining. If you have questions concerning the applicability of any recommendation or requirement listed in this procedure, contact the Principal Investigator/Laboratory Supervisor or the campus Chemical Hygiene Officer at [email protected]. Rev. Date: 2021-06-29 2 Flammable Liquids and Solids Chemical Class Standard Operating Procedure 2. Physical & Chemical Properties/Definition of Chemical Group Flammable liquid means a liquid having a flash point1 of not more than 199.4 °F (93 °C).
    [Show full text]
  • The Irreversible Cleavage of Histidine Residues by Diethylpyrocarbonate (Ethoxyformic Anhydride)
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Volume 72, number 1 FEBS LE’M-ERS December 1976 THE IRREVERSIBLE CLEAVAGE OF HISTIDINE RESIDUES BY DIETHYLPYROCARBONATE (ETHOXYFORMIC ANHYDRIDE) M. J. LOOSEMORE and R. F. PRATT Chemistry Department, Wesleyan University, Middletown, CT 06457, USA Received 4 October 1976 1 . Introduction 2. Materials and methods In aqueous solution at neutral or slightly acidic pH DEP was obtained from Aldrich Chemical Co. and values diethyl pyrocarbonate (ethoxyformic anhydride, used without further purification. The modification DEP) has been shown to modify histidine residues in reactions in 0.1 M phosphate buffer at pH 6.0 and proteins with considerable specificity [l-3] . For this 30°C of 0.2 mM solutions of imidazole, histidine, reason DEP has been widely used to test for the N-acetylhistidine and glycylhistidylglycine (all from presence of functional histidine residues at the active Sigma Chemical Co.) on addition of DEP to a final sites of enzymes; for example, phosphofructokinase concentration of l-5 mM (added as 5-20 ~1 of an [4], thermolysin [5,6], lactate dehydrogenase [7], acetonitrile or ethanol solution to 3 ml of imidazole pyruvate kinase [8] , and liver alcohol dehydrogenase solution) were followed spectrally with a Cary 14 [9]. The reagent is convenient since it reacts with spectrophotometer. The products of DEP-modified histidine to give an ultraviolet spectral change centered imidazole were isolated by chloroform extraction of a at 240 nm [2,3] from the intensity of which the number 12 h room-temperature reaction mixture obtained by of modified histidine residues can be estimated and the stirring in 20 ml of an acetonitrile solution of DEP to modification reaction can be reversed by cleavage of 1 .O litre of an aqueous solution of 2 mM imidazole in the product, Ncarbethoxyhistidine, with suitable 0.1 M phosphate buffer, pH 6.0 (final DEP concentra- nucleophiles such as hydroxylamine.
    [Show full text]
  • Diethyl Pyrocarbonate
    Proc. Nati. Acad. Sci. USA Vol. 82, pp. 8009-8013, December 1985 Biochemistry Diethyl pyrocarbonate: A chemical probe for secondary structure in negatively supercoiled DNA (chemical modification/alternating purines and pyrimidines/pBR322/Z-DNA) WINSHIP HERR Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 Communicated by J. D. Watson, August 9, 1985 ABSTRACT Purine residues located within regions of ity, which can change with the linking number of the DNA, DNA that have the potential to form left-handed Z-helical and (ii) binding ofantibodies directed against the Z-form. The structures are modified preferentially by diethyl pyrocarbon- first method detects the loss of supercoils and, therefore, ate; this hyperreactivity is dependent on the degree of negative decreasing linking number caused by the transition from a superhelicity of the circular DNA molecules. As negative right-handed B-helix to the left-handed Z-form. With the superhelical density increases, guanosines in a 32-base-pair second method, anti-Z-DNA antibodies are bound to nega- alternating G-C sequence and adenosines (but not guanosines) tively supercoiled molecules, and binding sites are identified in a 64-base-pair alternating A-C/G-T sequence become 5- to either by electron microscopy or by the retention ofantibody- 10-fold more reactive to diethyl pyrocarbonate. The negative bound DNAs to nitrocellulose filters (7). An advantage ofthe superhelical densities at which enhanced reactivity occurs are electrophoretic analyses is that formation of Z-DNA cannot similar to those reported for the point at which left-handed be affected by interactions with antibodies. Alternatively, the helices form within plasmids carrying these DNA sequences.
    [Show full text]
  • EAFUS: a Food Additive Database
    U. S. Food and Drug Administration Center for Food Safety and Applied Nutrition Office of Premarket Approval EAFUS: A Food Additive Database This is an informational database maintained by the U.S. Food and Drug Administration (FDA) Center for Food Safety and Applied Nutrition (CFSAN) under an ongoing program known as the Priority-based Assessment of Food Additives (PAFA). It contains administrative, chemical and toxicological information on over 2000 substances directly added to food, including substances regulated by the U.S. Food and Drug Administration (FDA) as direct, "secondary" direct, and color additives, and Generally Recognized As Safe (GRAS) and prior-sanctioned substances. In addition, the database contains only administrative and chemical information on less than 1000 such substances. The more than 3000 total substances together comprise an inventory often referred to as "Everything" Added to Food in the United States (EAFUS). This list of substances contains ingredients added directly to food that FDA has either approved as food additives or listed or affirmed as GRAS. Nevertheless, it contains only a partial list of all food ingredients that may in fact be lawfully added to food, because under federal law some ingredients may be added to food under a GRAS determination made independently from the FDA. The list contains many, but not all, of the substances subject to independent GRAS determinations. The list below is an alphabetical inventory representing only five of 196 fields in FDA/CFSAN's PAFA database. To obtain the entire database, including abstractions of over 7,000 toxicology studies performed on substances added to food as well as a search engine to locate desired information, order Food Additives: Toxicology, Regulation, and Properties, available in CD-ROM format from CRC Press.
    [Show full text]
  • Active-Site Characterization of Si Nuclease II
    Biochem. J. (1992) 288, 571-575 (Printed in Great Britain) 571 Active-site characterization of Si nuclease II Involvement of histidine in catalysis Sadanand GITE,* Gurucharan REDDY*t and Vepatu SHANKAR*t *Division of Biochemical Sciences, National Chemical Laboratory, Pune 411 008, India Modification of the histidine residues of purified SI nuclease resulted in loss of its single-stranded (ss)DNAase, RNAase and phosphomonoesterase activities. Kinetics of inactivation indicated the involvement of a single histidine residue in the catalytic activity of the enzyme. Furthermore, histidine modification was accompanied by the concomitant loss of all the activities of the enzyme, indicating the presence of a common catalytic site responsible for the hydrolysis of ssDNA, RNA and 3'-AMP. Substrate protection was not observed against Methylene Blue- and diethyl pyrocarbonate (DEP)-mediated inactivation. The histidine (DEP)-modified enzyme could effectively bind 5'-AMP, a competitive inhibitor of S1 nuclease, whereas the lysine (2,4,6-trinitrobenzenesulphonicracid)-modified enzyme showed a significant decrease in its ability to bind 5'-AMP. The inability of the substrates to protect the enzyme against DEP-mediated inactivation, coupled with the ability of the modified enzyme to bind 5'-AMP effectively, suggests the involvement of histidine in catalysis. INTRODUCTION 10600 M-1 * cm-' for deoxyribonucleotide and ribonucleotide mix- tures respectively (Curtis et al., 1966). One unit of ssDNAase or Single-strand specific nuclease from Aspergillus oryzae (Sl RNAase activity is defined as the amount of enzyme required to nuclease, EC 3.1.30.1) is an analytically important enzyme, used liberate 1 of acid-soluble nucleotides per minute under the extensively for the characterization of nucleic-acid structure /tmol assay conditions.
    [Show full text]
  • DEPC-Treated Water Rev 12/20
    FOR RESEARCH ONLY! DEPC-Treated Water Rev 12/20 ALTERNATE NAMES: RNase- and DNase-free water, RNase-free water, Molecular Biology Grade water, DEPC Water, Sterile water CATALOG #: M1500-100 100 ml M1500-1000 1 L APPEARANCE: Clear, Colorless liquid FEATURES: Ready-to-use Solution For RNA experiments RNase and DNase Free Molecular Biology Grade FORMULATION: 0.1 % v/v Diethyl Pyrocarbonate (DEPC) in water DESCRIPTION: DEPC is a non-specific inhibitor of Ribonucleases (RNases). To reduce degradation of RNA in experiments, water is treated with DEPC. The concentration of DEPC is 0.1%. Ultra-pure molecular biology grade water is treated with DEPC followed by auto-claving. Autoclaving inactivates DEPC by causing hydrolysis of DEPC and release of by-products ethanol and carbon-dioxide. DEPC modifies enzymes containing -NH, -SH, or -OH groups in their active sites. DEPC particularly reacts with Cys, His, Lys, Ser and Tyr residues of proteins. DEPC has a half-life of approximately 30 min in water. DEPC-Treated Water (0.1%) can be used with buffers such as PBS and MOPS but cannot be used with the buffers Tris and HEPES. Tris and HEPES make DEPC unavailable to inactivate RNase. DEPC-treated water should not be added to aqueous solutions of ammonia as it will result in the formation of urethane, a possible carcinogen. qPCR, Real-Time RT-PCR, cDNA synthesis and RNase protection assays APPLICATIONS: STORAGE TEMPERATURE: Room Temperature. Avoid long exposure to UV light. HANDLING: Do not take internally. Wear gloves and mask when handling the product! Avoid contact by all modes of exposure.
    [Show full text]
  • Reaction of Diethyl Pyrocarbonate with Nucleic Acid Components, I
    Proceedings ofthe National Academy of Sciences Vol. 67, No. 1, pp. 93-98, September 1970 Reaction of Diethyl Pyrocarbonate with Nucleic Acid Components, I. Adenine* Nelson J. Leonard, Jerome J. McDonald, and M. E. Reichmann DEPARTMENTS OF CHEMISTRY AND CHEMICAL ENGINEERING AND BOTANY, UNIVERSITY OF ILLINOIS, URBANA 61801 Communicated June 30, 1970 Abstract. The use of diethyl pyrocarbonate as a nuclease inhibitor in the preparation of RNA of high molecular weight has prompted a study of the possible reactions of this compound with nucleic acid components under the conditions generally employed for providing inhibition. The first substrate investigated was adenine, which has been found to undergo ring opening with the formation of 5(4)-N-carbethoxyaminoimidazole-4(5)-N'-carbethoxycarbox- amidine (II). This product was converted efficiently to isoguanine by treatment with ammonia. The structure of II was established by spectroscopy. For comparisons of reactivity and of spectroscopic and chromatographic prop- erties with the adenine-diethyl pyrocarbonate product, the compounds 9-car- bethoxyadenine, 6-N-carbethoxyaminopurine (V), and 6-ethylaminopurine were made; compound V was made by employing the 1-ethoxyethyl protecting group in the synthetic sequence. Purine compounds can be converted to 9-(1-ethoxy- ethyl) derivatives simply by refluxing in acetal. The facile reaction of adenine with diethyl pyrocarbonate illustrates the im- portance of gaining information as to the fate of various nucleic acid components in the presence of diethyl pyrocarbonate. The successful preparation of high molecular weight, biologically active RNA depends on the rapid inactivation of nucleases in the early steps of the isolation. Conservation of biological activity upon prolonged storage also requires the total absence of nuclease activity in these preparations.
    [Show full text]
  • Flammable Liquids and Solids Chemical Class Standard Operating Procedure
    Flammable Liquids and Solids Chemical Class Standard Operating Procedure Flammable Liquids and Solids H224 H225 H226 H227 H228 Areas with blue text indicate that information must be provided or modified by researcher prior to the SOP approval. This SOP is not a substitute for hands-on training. Print a copy and insert into your laboratory SOP binder. Department: Chemistry Date SOP was written: Monday, October 24, 2016 Date SOP was approved by PI/lab supervisor: Name: R. Sarpong Principal Investigator: Signature: ______________________________ Name: Melissa Hardy/Justin Jurczyk Internal Lab Safety Coordinator or Lab Manager: Lab Phone: 406-696-1225/412-728-1952 Office Phone: 510-642-6312 Name: Melissa Hardy/Justin Jurczyk Emergency Contact: Lab Phone: 406-696-1225/412-728-1952 Latimer Hall Location(s) covered by this SOP: 831,832,834,836,837,838,839,842,844,847,849 1. Purpose This SOP covers the precautions and safe handling procedures for the use of Flammable Liquids and Solids. For a list of Flammable Liquids and Solids covered by this SOP and their use(s), see “List of Chemicals”. Procedures described in Section 12 apply to all materials covered in this SOP. If you have questions concerning the applicability of any recommendation or requirement listed in this procedure, contact the Principal Investigator/Laboratory Supervisor or the campus Chemical Hygiene Officer at [email protected]. Rev. Date: 09Sept2016 1 Flammable Liquids and Solids Chemical Class Standard Operating Procedure 2. Physical & Chemical Properties/Definition of Chemical Group Flammable liquid means a liquid having a flash point1 of not more than 199.4 °F (93 °C).
    [Show full text]
  • 1,2-Bis[(2R ,5R )-2,5-Diethylphospholano]Benzene
    TABELLA DI STIMA CONSUMO ANNUALE LOTTO 1B UNIPV REAGENTI CHIMICI QUANTITA' Unità di CAS Number PRODOTTO ANNUA Misura 136705-64-1 (−)-1,2-Bis[(2R ,5R )-2,5-diethylphospholano]benzene 0,350 g 83-88-5 (-)-RIBOFLAVIN 87,500 g 225937-10-0 (+)-CATECHIN HYDRATE 17,500 g 706-14-9 (+)-GAMMA-DECALACTONE, >=97% 350,000 g 75-56-9 (+/-)-PROPYLENE OXIDE 0,8750 l 480438-44-6 (1,3-DIOXAN-2-YLETHYL)MAGNESIUM BROMIDE 0,350 l 470480-32-1 (1S ,1S ′,2R ,2R ′)-1,1′-Di-tert -butyl-(2,2′)-diphospholane 0,350 g 919-30-2 (3-AMINOPROPYL)TRIETHOXYSILANE, >=98.0% 0,700 l 14867-28-8 (3-IODOPROPYL)TRIMETHOXYSILANE, >=95.0% 0,08750 l 4420-74-0 (3-MERCAPTOPROPYL)TRIMETHOXYSILANE, 95% 700,000 g 2712-78-9 (BIS(TRIFLUOROACETOXY)IODO)BENZENE, 97% 175,000 g 1833-51-8 (CHLOROMETHYL)DIMETHYLPHENYLSILANE, 98% 70,000 g 5293-84-5 (CHLOROMETHYL)TRIPHENYLPHOSPHONIUM 87,500 g 364732-88-7 (R )-(–)-4,12-Bis(diphenylphosphino)-[2.2]-paracyclophane 0,350 g (R )-(−)-5,5′-Bis[di(3,5-di-tert -butyl-4-methoxyphenyl)phosphino]-4,4′-bi-1,3- 566940-03-2 benzodioxole 0,350 g 5989-27-5 (R)-(+)-LIMONENE, 98% 0,350 l 138517-61-0 (R,R)-DACH-PHENYL TROST LIGAND, 95% 0,8750 g 5989-54-8 (S)-(-)-LIMONENE, >=95% 3500,000 g 29394-58-9 (S)-(+)-1-IODO-2-METHYLBUTANE 17,500 g (S)-2-(4′-Bromo-biphenyl-4-sulfonylamino)-3-methyl-butyric acid hydrate 0,01750 g 138517-65-4 (S,S)-ANDEN-PHENYL TROST LIGAND 0,350 g 1066-54-2 (TRIMETHYLSILYL)ACETYLENE, 98% 175,000 g 18107-18-1 (TRIMETHYLSILYL)DIAZOMETHANE, 2.0 M in diethyl ether 0,08750 l 436863-50-2 1,1''-BIS((2S,5S)-2,5-DIETHYLPHOSPHOLANO 0,350 g 530-62-1 1,1'-CARBONYLDIIMIDAZOLE,
    [Show full text]
  • Technical Report for the Substantial Modification Rule for 62-730, F.A.C
    Technical Report for the Substantial Modification Rule for 62-730, F.A.C. Prepared for the Hazardous Waste Regulation Section Florida Department of Environmental Protection By Kendra F. Goff, Ph. D. Stephen M. Roberts, Ph.D. Center for Environmental & Human Toxicology University of Florida Gainesville, Florida August 1, 2008 During an adverse event, such as a fire or explosion, hazardous materials from a storage or transfer facility may be released into the atmosphere. The potential human health impacts of such a release are assessed through air modeling coupled with chemical-specific inhalation criteria for short-term exposures. With this approach, distances from the facility over which differing levels of health effects from inhalation of airborne hazardous materials are expected can be predicted. Because the movement in air and toxic potency varies among chemicals, the potential impact area for a facility is dependent upon the chemicals present and their quantities. The impact area can be calculated for a facility under current and possible future conditions. This information can be used to determine whether proposed changes in storage conditions or the nature and quantities of chemicals handled would result in a substantial difference in the area of potential impact. The following sections provide technical guidance on how impact areas for facilities handling hazardous materials under Chapter 62-730, F.A.C. should be determined. Air modeling. Any model used for the purposes of demonstration must be capable of producing results in accordance with worst-case scenario provisions of Program 3 of the Accidental Release Prevention Program of s. 112(r)(7) of the Clean Air Act.
    [Show full text]
  • Activation of Carboxylic Acids by Pyrocarbonates
    This article was downloaded by: [University of Delaware] On: 11 June 2012, At: 08:03 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Organic Preparations and Procedures International: The New Journal for Organic Synthesis Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/uopp20 ACTIVATION OF CARBOXYLIC ACIDS BY PYROCARBONATES. SCOPE AND LIMITATIONS. A REVIEW V. F. Pozdnev a a Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, Pogodinskaya st., 10, Moscow, 119832, RUSSIA Available online: 09 Feb 2009 To cite this article: V. F. Pozdnev (1998): ACTIVATION OF CARBOXYLIC ACIDS BY PYROCARBONATES. SCOPE AND LIMITATIONS. A REVIEW, Organic Preparations and Procedures International: The New Journal for Organic Synthesis, 30:6, 631-655 To link to this article: http://dx.doi.org/10.1080/00304949809355325 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
    [Show full text]
  • Table 4: Protective Action Criteria (PAC) Rev 27 Based on Applicable 60-Minute Aegls, Erpgs, Or Teels
    Table 4: Protective Action Criteria (PAC) Rev 27 based on applicable 60-minute AEGLs, ERPGs, or TEELs. The chemicals are listed in 3 alphabetical order and the values are presented in mg/m . February 2012 Table 4 is an alphabetical list of the chemical substances and their corresponding PAC values in mass per unit volume (mg/m3). The conversion of ppm to mg/m3 was carried out assuming normal temperature and pressure, 25°C and 760 mm Hg. The columns presented in Table 4 provide the following information: Heading Definition No. The ordered numbering of the chemicals as they appear in this alphabetical listing Chemical Name The name of the chemical substance submitted to the PAC development team CASRN The Chemical Abstracts Service Registry Number1 for this chemical PAC-1 Based on the applicable AEGL-1, ERPG-1, or TEEL-1 value PAC-2 Based on the applicable AEGL-2, ERPG-2, or TEEL-2 value PAC-3 Based on the applicable AEGL-3, ERPG-3, or TEEL-3 value Chemicals for which AEGLs are available have their chemical name, CASRN, and AEGL values displayed in a bolded and larger font. Chemicals for which ERPGs are available, but not AEGLs, have their chemical name, CASRN, and ERPG values displayed in a bolded font. Chemicals for which TEELs are available, but no AEGLs or ERPGs, have their chemical name, CASRN, and values displayed using a regular font. Additional information on PAC values and TEEL values and links to other sources of information is provided on the Subcommittee on Consequence Assessment and Protective Actions (SCAPA) webpage at: http://orise.orau.gov/emi/scapa/teels.htm.
    [Show full text]