Possible Interaction: Hydrogen Peroxide and Tryptophan

“Exposure of IDO-expressing cells or recombinant human IDO (rIDO) to H2O2 inhibited dioxygenase activity in a manner abrogated by l-Trp.”

“The promotion of H2O2 consumption by peroxidase substrates, NO consumption, and IDO nitration was inhibited by l-Trp.”

“Formation of the dioxygen adduct and oxidation of Trp were accelerated by the addition of small amounts of hydrogen peroxide , and both processes were inhibited in the presence of either superoxide dismutase or catalase.”

“It was confirmed that superoxide anions (O2−) and hydrogen peroxide (H2O2) were formed during the light exposure, and that their formation could be significantly inhibited by the addition of tryptophan or mannitol, scavenger of hydroxyl radicals.”

“We found that some metabolites of tryptophan and medicines induce fluorescence by photoirradiation in the presence of idrogen peroxide and established systems based on liquid chromatography with detection by the fluorescence reactions.”

“Oxidation of tryptophan by catalytic metMb and hydrogen peroxide resulted in spin trap-inhibitable oxygen consumption, consistent with formation of a peroxyl radical.”

“Modification of tryptophan residues with H2O2 also indicates different classes of these residues available for oxidation at different concentrations of the oxidant.”

“The activity of the Val 73 --> Trp mutant drastically decreases to less than 5% of the initial activity after incubation with hydrogen peroxide.”

“Instead, the activity enhancement observed is likely to result from the protective effect of tryptophan against H2O2 inactivation.”