title: Oxidation of nitroxide radicals by the reaction of hemoglobin with hydrogen peroxide.
abstract: The ESR signal of 4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine in hemoglobin solution decreased drastically by the addition of hydrogen peroxide. The results of ion-exchange chromatography and sodium tetraphenylborate on the reaction solution showed an oxidation of the nitroxide radical to cation form. On the basis of the comparison of thin layer-chromatogram with the reaction products of the nitroxide radicals with HCl or Br2, the formation of 4-hydroxy-1-oxo-2,2,6,6- tetramethylpiperidinium cation was demonstrated. This result was supported by the 13C NMR measurement.
mesh_terms: D002412:Cations; D002852:Chromatography, Ion Exchange; D002855:Chromatography, Thin Layer; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D006454:Hemoglobins; D006851:Hydrochloric Acid; D006861:Hydrogen Peroxide; D010084:Oxidation-Reduction; D013113:Spin Labels; D013775:Tetraphenylborate
chemical_list: D002412:Cations; D003497:Cyclic N-Oxides; D006454:Hemoglobins; D013113:Spin Labels; D013775:Tetraphenylborate; D006861:Hydrogen Peroxide; D006851:Hydrochloric Acid; C001803:tempol