Unexpected Reaction Pathway of the Alpha-Aminoalkyl Radical Derived from One-Electron Oxidation of S-Alkylglutathiones

Laser flash photolysis and high-resolution mass spectrometry were used to investigate the mechanism of one-electron oxidation of two S-alkylglutathiones using 3-carboxybenzophenone (3CB) as a photosensitizer. This report indicates an unexpected reaction pathway of the α-aminoalkyl radical cation (αN(+)) derived from the oxidation of S-alkylglutathiones. Instead of a common hydrolysis reaction of αN(+) reported earlier for methionine and other sulfur-containing aminoacids and peptides, an intramolecular ring-closure reaction was found for S-alkylglutathiones.