FORMATION BY HYDROGEN PEROXIDE OR 254 nm RADIATION OF A NEAR-UV CHROMOPHORE FROM PEPTIDE-BOUND CYSTEINE

Abstract Treatment of glutathione or N-acetylcysteinamide in water with hydrogen peroxide, or with 254 nm radiation together with molecular oxygen, results in the formation of a near-UV chromophore having maximal absorption at 305 nm. From examination of related compounds, it is apparent that the N-acylcysteinamide residue is the key element required for generation of the 305 nm chromophore. The structure of this near-UV chromophore is stable to base but unstable in aqueous acid, is relatively sensitive to oxidation by hydrogen peroxide but is only very slowly reduced by sodium borohydride and displays good thermal stability at 50°C.