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

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 CH2 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 ε-N-centered Lys radical.