title: Sulfate anion free radical formation by the peroxidation of (Bi)sulfite and its reaction with hydroxyl radical scavengers.
abstract: The one-electron oxidation of (bi)sulfite is catalyzed by peroxidases to yield the sulfur trioxide radical anion (SO3-), a predominantly sulfur-centered radical as shown by studies with 33S-labeled (bi)sulfite. This radical reacts with molecular oxygen to form a peroxyl radical. The subsequent reaction of this peroxyl radical with (bi)sulfite has been proposed to form the sulfate anion radical, which is nearly as strong an oxidant as the hydroxyl radical. We used the spin trapping electron spin resonance technique to provide for the first time direct evidence for sulfate anion radical formation during (bi)sulfite peroxidation. The sulfate anion radical is known to react with many compounds more commonly thought of as hydroxyl radical scavengers such as formate and ethanol. Free radicals derived from these scavengers are trapped in systems where (bi)sulfite peroxidation has been inhibited by these scavengers.
authors.affiliation: Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709.
authors.forename: C
authors.initials: C
authors.lastname: Mottley
authors.forename: R P
authors.initials: RP
authors.lastname: Mason
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D006735:Horseradish Peroxidase; D006878:Hydroxides; D010084:Oxidation-Reduction; D013113:Spin Labels; D013431:Sulfates; D013447:Sulfites; D013461:Sulfur Oxides
chemical_list: D005609:Free Radicals; D006878:Hydroxides; D013113:Spin Labels; D013431:Sulfates; D013447:Sulfites; D013461:Sulfur Oxides; D006735:Horseradish Peroxidase