TY - JOUR T1 - Superoxide Radical as an Intermediate in the Oxidation of Hydroxylamines by Mixed Function Amine Oxidase JF - Molecular Pharmacology JO - Mol Pharmacol SP - 131 LP - 137 VL - 15 IS - 1 AU - ELMER J. RAUCKMAN AU - GERALD M. ROSEN AU - BARBARA B. KITCHELL Y1 - 1979/01/01 UR - http://molpharm.aspetjournals.org/content/15/1/131.abstract N2 - Previous observations have shown that mixed function amine oxidase (MFAO), a flavo-protein, is responsible for the oxidation of hydroxylamines to nitroxides. We had assumed that the hydroperoxyflavin directly attacked the hydroxylamine giving the hydroxylamine oxide as an intermediate which rapidly decomposed to yield a nitroxide and a hydroxyl radical. A kinetic investigation showed that MFAO does not directly attack the hydroxylamine but suggested that MFAO releases an oxidizing agent that is responsible for hydroxylamine oxidation. The Haber-Weiss reaction, known to produce hydroxyl radicals, was shown not to be involved in the formation of nitroxide free radicals. It was found that superoxide is solely responsible for MFAO mediated nitroxide formation. ACKNOWLEDGMENTS We thank Dr. Dan. Ziegler, University of Texas, for his most generous gift of purified mixed function amine oxidase. We are grateful to Dr. Henry Fisher of the Environmental Protection Agency for the use of his Varian Associates E-9 spectrometer. ER -