Reactions of dichloride anion radicals with aliphatic peptides in aqueous solutions.

Rate constants for the reactions of dichloride anion radicals with aliphatic peptides were determined by a conventional flash photolysis of 1 M solutions of potassium chloride containing aliphatic peptides. The rate constants were found to increase with increasing number of C-H bond. Partial rate constants were assigned to each C-H bond of the aliphatic peptides, as estimated for the reactions of hydroxyl radicals with the same substrates. Trend in the partial rate constants and the effect of a protonated amino group on the reactivity indicate a reaction mechanism, hydrogen atom abstraction, similar to hydroxyl radicals.