THE EFFECT OF AROMATIC AMINO ACIDS ON THE PHOTOCHEMISTRY OF A DISULFIDE: ENERGY TRANSFER AND REACTION WITH HYDRATED ELECTRONS

Abstract—The decomposition of dithioglycolic acid in oxygen‐free solutions illuminated by low‐intensity 254 nm light at pH 1.5‐4.7 is enhanced by light absorbed in tyrosine. This occurs through an interaction with excited tyrosine, leading to the formation of excited dithioglycolic acid. At pH 6‐1 an additional pathway appears, through the formation of a hydrated electron from excited tyrosine. In the presence of tryptophan at pH 1 ‐2–6‐1 the pathway involving sensitized formation of excited dithioglycolic acid is much less important, and that due to hydrated‐electron (or H) formation from excited tryptophan of greater importance.