THE TRIPLET STATE OFPYRIDOXAL–5'-PHOSPHATE IN LASER FLASH PHOTOLYSIS

Abstract— Sensitization and quenching experiments demonstrate that laser flash photolysis ofpyridoxal–5'-phosphate populates a triplet state about 244 kJ/mol. Excitation by the 337.1-nm photons from a nitrogen laser generated transient absorption in the 400-nm region which decayed with a fast first order component on a much slower one. Xanthone photosensitized the same absorption; oxygen, nitric oxide, biacetyl, and 1,3-cyclo-hexadiene quenched it. Spectra and lifetimes suggest that the triplet state leads to radical formation.