Laser flash photolysis study of cyclic-Phe-His in aqueous solution

Photolysis and photosensition of cyclic-phenylalanine-histidine (cyclic-Phe-His) in aqueous solution were studied using KrF laser flash photolysis (248nm). Photoionization and photodissociation of cyclic-Phe-His in Phe-site occured and the characteristic absorption at 320nm and 410nm have been observed. From changes of the absorption peaks and kinetic analysis, the reaction mechanism of photoionization and photodissociation has been suggested, a series of kinetic parameters have been obtained. Using acetone as a photosensitizer, and N-3 . as an oxidant by pulse radiolysis method, the induced oxidation of cyclic-Phe-His in aqueous solution has been also reported in this paper, results similar to the photoionization of cyclic-Phe-His have been found.