title: The use of 3-bromopropionic acid for the determination of protein thiol groups.
abstract: S-Carboxymethylcysteine, formed by the reaction of iodoacetic acid with cysteine, was found to undergo intramolecular cyclization to yield 3-oxo-(2H,3H,5H,6H-1,4-thiazine)-5-carboxylic acid. The cyclization was studied under various conditions and the product was isolated and characterized. S-Carboxyethylcysteine, formed by the reaction of 3-bromopropionic acid with cysteine, did not undergo the cyclization reaction. The use of 3-bromopropionic acid was examined as an alternative to iodoacetic acid for the protection and determination of protein thiol groups.
mesh_terms: D000478:Alkylation; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001322:Autoanalysis; D001966:Bromine; D002247:Carbon Isotopes; D002264:Carboxylic Acids; D002852:Chromatography, Ion Exchange; D003500:Cyclization; D003545:Cysteine; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D007328:Insulin; D007461:Iodoacetates; D008745:Methylation; D011422:Propionates; D011506:Proteins / Q000032:analysis*; D013438:Sulfhydryl Compounds / Q000032:analysis*; D013552:Swine; D013843:Thiazines
chemical_list: D000596:Amino Acids; D002247:Carbon Isotopes; D002264:Carboxylic Acids; D007328:Insulin; D007461:Iodoacetates; D011422:Propionates; D011506:Proteins; D013438:Sulfhydryl Compounds; D013843:Thiazines; D003545:Cysteine; D001966:Bromine