THE PHOTOLYSIS OF CYSTINE IN ACIDIC AQUEOUS SOLUTION

Publisher Website
Google Scholar
Abstract
Abstract— Quantum yields of cysteine, ammonia, 1‐amino,1′‐oxo,2,2′‐dithiodipropionicacid (AODT–DPA), alanine, alanine 3‐sulphinic acid, cysteic acid, and serine have been determined in aqueous oxygenated and deaerated cystine solutions irradiated with 254 nm radiation. From the effect of methanol, ethanol and propanol‐2 on the quantum yields of cysteine, ammonia, AODT‐DPA and alanine, it is concluded that (a) the S–S bond is broken with high quantum efficiency, (b) C–S and C–N bonds do not undergo primary photolytic fission, and (c) all the AODT–DPA, but only about 12 per cent of the ammonia, is free‐radical in origin. The production of pyruvic acid at the expense of AODT–DPA in irradiated cystine solutions containing alanine provides further evidence that AODT–DPA has free‐radical precursors. Reaction schemes are proposed for the radical‐induced production of keto acid and ammonia in oxygenated and deaerated solutions.

This publication has 12 references indexed in Scilit: