title: Free radical metabolites of L-cysteine oxidation.
abstract: The oxidation of L-cysteine by horseradish peroxidase in the presence of oxygen forms a thiyl free radical as demonstrated with the spin-trapping ESR technique. Reactions of this thiyl free radical result in oxygen consumption, which is inhibited by the spin trap 5,5'-dimethyl-1-pyrroline-N-oxide. Cysteine sulfinic acid, a cysteine metabolite, is a poorer substrate for horseradish peroxidase than cysteine and is oxidized to form both sulfur-centered and carbon-centered free radicals.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D003545:Cysteine / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D006735:Horseradish Peroxidase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000378:metabolism*; D013113:Spin Labels
chemical_list: D005609:Free Radicals; D013113:Spin Labels; D006735:Horseradish Peroxidase; D010544:Peroxidases; D003545:Cysteine