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Assessment of a Radiochemical Method Using 14 C‐Labeled N‐Ethylmaleimide as a Reagent for Sulfhydryl Determination with Assays on β‐Lactoglobulin and Insulin
Author(s) -
Lai TzenSon
Publication year - 1971
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.197100018
Subject(s) - chemistry , reagent , n ethylmaleimide , cysteine , glutathione , mole , chromatography , peptide , hydrolysis , disulfide bond , biochemistry , enzyme , organic chemistry
A radiochemical method using 14 C‐labeled N‐ethylmaleimide (NEM‐ 14 C) as a reagent for sulfhydryl determination is reassessed and described in detail. The method is based on the activity of 14 C‐labeled S‐succinyl‐L‐cysteine (III‐ 14 C) recovered from the controlled hydrolysis of the NEM‐ 14 C treated sulfhydryl‐containing peptide and the correlation between III‐ 14 C and SH content established with glutathione. It is simple, accurate and highly sensitive and is not affected by disulfide group as indicated by experiments with insulin. Good result is obtained from tests with β‐lactoglobulin. It gives a value of 1.94 mole SH per mole protein, which is close to that generally accepted.