New Color Test for Thiols and Thiolesters

Benesch, Ruth E.; Gutcho, Marcia; Laufer, Louis

doi:10.1126/science.123.3205.981

Cited by 64 publications

(16 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…KOH in absolute isopropanol according to Benesch et al (1956). The CoASH-NEM complex had an Rf similar to that of acetyl-CoA and was eluted with it.…”

Section: E J Mitzen a N D A H Koeppenmentioning

confidence: 99%

Malonate, Malonyl‐Coenzyme A, and Acetyl‐Coenzyme A in Developing Rat Brain

Mitzen

Koeppen

1984

Journal of Neurochemistry

View full text Add to dashboard Cite

Free malonate, malonyl-coenzyme A (malonyl-CoA), and acetyl-CoA were assayed in rat brain at developmental ages from the 20th day of gestation to 60 days of postnatal life. The determination of malonate was based on its conversion to malonyl-CoA and decarboxylation to acetyl-CoA by enzyme extracts from Pseudomonas fluorescens. The resulting acetyl-CoA reacted with [4-14C]oxaloacetate to form [5-14C]citrate, which was isolated by TLC. Malonyl-CoA in perchloric acid extracts from brain was converted to acetyl-CoA by rat liver mitochondrial malonyl-CoA decarboxylase (EC 4.1.1.9). Acetyl-CoA derived from this step was assayed by a modified CoA-cycling procedure. Brain acetyl-CoA was also assayed by CoA cycling. Prenatal brain contained no free malonate but malonyl-CoA was present. The acetyl-CoA level was relatively high just prior to birth and declined slightly with growth. Malonate concentrations after birth rose rapidly to reach 192 nmol/g wet weight at 60 days. Adult levels for malonyl-CoA and acetyl-CoA were 1.83 and 1.90 nmol/g wet weight, respectively. The origin and natural role of free malonate in brain are not known but deacylation of malonyl-CoA by reversal of the malonyl-CoA synthetase reaction is postulated. Rat liver and kidney also contain substantial concentrations of free malonate.

show abstract

“…KOH in absolute isopropanol according to Benesch et al (1956). The CoASH-NEM complex had an Rf similar to that of acetyl-CoA and was eluted with it.…”

Section: E J Mitzen a N D A H Koeppenmentioning

confidence: 99%

Malonate, Malonyl‐Coenzyme A, and Acetyl‐Coenzyme A in Developing Rat Brain

Mitzen

Koeppen

1984

Journal of Neurochemistry

View full text Add to dashboard Cite

show abstract

“…This decrease, referred to as "the A-SH reaction," was also demonstrated in dialyzed hemolysates. The pH optimum for the reaction was found to be 6.8-7.0, A-SH being reduced about 30 per cent at pH 6.1 and at 7.3.…”

mentioning

confidence: 90%

“…Preparation of cell-free extracts, ribosomes and supernatant: E. coli B was cultivated and washed, and the crude cell-free extract was made by grinding with alumina and extracting with 3 volumes of 0.005 M Tris-HCl pH 7.3 and 0.01 M Mg++, containing 5 ug deoxyribonuclease (I)Nase) per ml as described elsewhere. 6 The washed cells could be kept frozen. In some experiments the extracts were fractionated into ribosomes and supernatant by 2 hr centrifugation at 100,000g.…”

mentioning

confidence: 99%

Reversible Changes in the Nem-Reactive —Sh Groups of Hemoglobin on Oxygenation-Deoxygenation

Morell¹,

Hoffman²,

Ayers³

et al. 1962

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

In a previous communication the reaction of N-ethylmaleimide (NEM) with the thiols of intact human erythrocytes was described.1 The principal sites of reaction are the p-chains of hemoglobin2 and intracellular glutathione. Average values of 2.35 and 0.45 equivalents of HbSH and GSH respectively per mole of hemoglobin have been found for normal red cells. The conditions used were NEM/Hb = 8,-1 hr, 250C, pH 6.8. NEM is relatively unstable above pH 7 and reacts readily with thiols at pH 6.8.3 As shown in Figure 1, the uptake of NEM by both erythro-3.0 e-~~~~GSH 2.5 _ 2.0J 0 Uj 1.0 , 0.5 , 10 20 30 40 50 60 70 M N U T E S FIG. 1.-Rate of NEM-reaction with intact erythrocytes and dialyzed stroma-free hemolysates. NEM 0.002 M, pH 6.8, 23 1 10C, molar ratio NEM/Hb = 8. See Table 1 for procedure and calculation of equiv-SH/mole Hb, uncorrected for GSH.cytes and dialyzed hemolysates, measured by decrease in absorption at 300 m/, is rapid during the first 30 minutes and very slow after one hour. The reagent exhibits a relatively high degree of specificity in reacting rapidly with -SH groups.3-8 No significant amounts of NEM are bound when the -SH groups of hemoglobin are alkylated8 and the measurement of -SH by amperometric titration has been correlated with OD3oo.2 Reactions with other sites on the protein, as well as the imidazole-catalyzed polymerization of NEM,9 are apparently secondary. Correlations of OD)oo with S-cysteinosuccinic acid formed on hydrolysis of NEM-treated proteins also indicate that the rapid reaction of NEM with proteins is limited to condensation with -SH groups.7' 10The purpose of the present communication is to report evidence that the reactive -SH groups of hemoglobin undergo reversible changes on oxygenation-deoxygena-, tion. As measured by reaction of NEM with erythrocytes for one hr at pH 6.8, the number of -SH groups decreased on deoxygenation from about 2 (2.3 ± 0.2) to 1057

show abstract

“…A number of references were also found from a literature search (2,3,(5)(6)(7)(8)10,11,(13)(14)(15)(16)(18)(19)(20)(21)(22)(23)(24)(25)(26)29,30,(32)(33)(34)44,46,47,49,(51)(52)(53)(54)(56)(57)(58)(62)(63)(64)(65). All these reactions were identified as potentially worthwhile and were examined in a t least abstract form to determine if the general criteria for the test reaction were met a t least in part.…”

Section: Literature Surveymentioning

confidence: 99%

Colorimetric Methods for Field Measurement of Sulfide Odorants

Knight¹,

Verma²

1977

Product R&D

View full text Add to dashboard Cite

He received his Ph.D. degree in Physical Chemistry from the University of Alberta. He joined the University of Saskatchewan as Assistant Professor of Chemistry in 1964 and was made Associate Professor in 1968, Professor in 1972, and Department Head in 1976. He is the author of an undergraduate textbook, "Introductory Physical Chemistry", some 36 research papers, and one patent. His main research area is the photochemistry and photophysics of thiocarbonyls and other sulfur containing compounds. His work on some fundamental chemical properties of these compounds led to his recent investigations of natural gas odorants. Dr. Knight is a Fellow of the Chemical Institute of Canada.Arun Verma earned his B.Sc. (1966) and M.Sc. (1968) in Chemical Engineering from Panjab University in India. He obtained his Ph.D. (1971) in Chemical Engineering from the University of New Brunswick in Canada. After spending ten months at Laval University in Quebec, he joined the Saskatchewan Power Corporation in 1972. He was Project Leader for establishing the Corporation's province-wide environmental monitoring system before joining the Research & Development Centre as a Research Engineer, where presently he is In-Charge of the Chemistry and Chemical Engineering Section. His assignments include energy R&D work and process and techno-economic feasibility studies in the energy field, especially synthetic fuels. He has 14 publications and 2 patents in the fields of energy, environment, and catalysis.

show abstract

New Color Test for Thiols and Thiolesters

Cited by 64 publications

References 5 publications

Malonate, Malonyl‐Coenzyme A, and Acetyl‐Coenzyme A in Developing Rat Brain

Malonate, Malonyl‐Coenzyme A, and Acetyl‐Coenzyme A in Developing Rat Brain

Reversible Changes in the Nem-Reactive —Sh Groups of Hemoglobin on Oxygenation-Deoxygenation

Colorimetric Methods for Field Measurement of Sulfide Odorants

Contact Info

Product

Resources

About