Carbon-and nitrogen-centered radicals produced from L-lysine by radiation-induced oxidation : A pulse radiolysis study

Abstract Radical species generated from the reactions of a basic amino acid, l -lysine (Lys), with hydroxyl radicals ( OH) and sulfate radical anion ( SO 4 - ) have been detected by the method of pulse radiolysis. On the basis of electron transfer reactivities toward tetranitromethane (TNM), it was demonstrated that reducing carbon-centered radicals are generated as a result of hydrogen abstraction from CH 2 of Lys with a G -value of 1.9 × 10 −7 mol J −1 . On the other hand, direct oxidation of l -Lys by SO 4 - formed a transient species with different spectroscopic properties, most likely, the e-N-centered Lys radical.