Gamma radiolysis of oxygenated aqueous solutions of tryptophan

The decomposition yield of tryptophan and radiation chemical yields of stable products - N-formylkynurenine (FK) and hydrogen peroxide (H2O2) were measured in oxygenated solutions at various tryptophan concentrations. A lower yield of H2O2 than expected was observed. However, results obtained by following the effect of pH on FK- and H2O2-formation indicate that the loss of H2O2 is due to the reaction of Trp-OH adducts with O2- radicals which are precursors of hydrogen peroxide. N-formyl-kynurenine is formed in the reaction of Trp-OH with both O2-and O2. (author)