Reaction of S-(2-amino-2-carboxyethylsulfonyl)-l-cysteine with thiosulfate: Synthesis of l-alanine sulfodisulfane and application to the determination of thiosulfate

✍ Scribed by Toshihiko Ubuka; Noriyoshi Masuoka; Haruhiko Mikami; Miyabi Taniguchi

• Book ID: 102986089
• Publisher: Elsevier Science
• Year: 1984
• Tongue: English
• Weight: 556 KB
• Volume: 140
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(84)90192-1

✦ Synopsis

A new reaction of S-(2-amino-2-carboxyethylsulfonyl)-L-cysteine (ACESC) with thiosulfate is described. The reaction proceeded quantitatively in formic or acetic acid solutions, yielding equimolar amounts of L-alanine sulfodisulfane (2-amino-2-carboxyethyl sulfodisulfane) and L-alanine 3-sulfinic acid. L-Alanine sulfodisulfane was obtained as pure monosodium salt; the yield was 92% of the theoretical. A new method is described for the determination of thiosulfate. The method is based on the quantitative reaction between ACESC and thiosulfate, and L-alanine sulfodisulfane, one of the reaction products, was determined using acid ninhydrin reagent 2 of M. K. Gaitonde (1967, Biochem. J. 104, 627-633). The recovery was over 95%. When samples contained sulfite in addition to thiosulfate, S-sulfo-L-cysteine (T. Ubuka et al., 1982, Anal. Biochem. 126, 273-277) was produced in addition to L-alanine sulfodisulfane by the treatment with ACESC. Both products were separated by a small Dowex 1 column and determined with the acid ninhydrin reagent 2. The recoveries were over 95%. The new method was applied to the thiosulfate sulfurtransferase reaction, in which thiosulfate, a substrate, and sulfite, a product, were determined separately.