| Abstract: | A new reaction of S-(2-amino-2-carboxyethylsulfonyl)-
-cysteine (ACESC) with thiosulfate is described. The reaction proceeded quantitatively in formic or acetic acid solutions, yielding equimolar amounts of
-alanine sulfodisulfane (2-amino-2-carboxyethyl sulfodisulfane) and
-alanine 3-sulfinic acid.
-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
-alanine sulfodisulfane, one of the reaction products, was determined using acid ninhydrin reagent 2 of 7.]. The recovery was over 95%. When samples contained sulfite in addition to thiosulfate, S-sulfo-
-cysteine (6.]) was produced in addition to
-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. |
