Physical chemical processes of acetone triplet with aromatic almino acid-containing peptides

The photochemical processes of triplet acetone with aromatic amino acid-con taining peptides were investigated in neutral aqueous solution using KrF(24 8 nm) laser flash photolysis, In the presence of acetone, the formation of excited triplet states of tryptophan residues and radicals(Trp/N-.) via a t riplet-triplet(T-T) energy transfer and an electron transfer respectively, was observed in case of Trp-Phe, Trp-Gly and n-formyl-Met-Trp, while only p henolic hydroxy radical(Tyr/O-.), via an electron transfer, was observed in case of Phe-Tyr. Furthermore, triplet acetone induced radical transformati on: Trp/N-.-Tyr-->Trp-Tyr/O-. was observed directly, and the transformation resulting from intramolecular electron transfer was suggested.