The reaction of the hydrated electron with amino acids, peptides, and proteins in aqueous solutions. Tryptophyl peptides

The reaction rate constants of e(aq)^- wih glycyl-tryptophan, glycyl-glycyl-tryptophan, and glycyl-tryptophyl-glycine were determined. The rate constant of each peptide was found to be pH dependent. This is attributed to the overall charge of the molecule. It was found that the increase of carbonyl groups increases the e(aq)^- reactivity toward the peptide. The transient absorbing spectra resulting from the reaction of e(aq)^- with tryptophyl peptides showed the presence of an electron adduct on the indole and a deaminated radical. The yield of the last species was found to be on the order of 40%. The OH reaction with glycyl-tryptophan was also investigated. It was shown that its reaction rate constant and the transient produced are similar to that observed with tryptophan.