title: Plasma membrane NADH-coenzyme Q0 reductase generates semiquinone radicals and recycles vitamin E homologue in a superoxide-dependent reaction.
abstract: We investigated the ability of plasma membrane CoQ reductase (PMQR) purified from pig liver to reduce phenoxyl radicals of a vitamin E homologue, Trolox. We report that NADH-driven one-electron reduction of CoQ0 catalyzed by PMQR produced CoQ0 semiquinone radical and CoQoH2. These in turn, recycle vitamin E homologue, Trolox, via reducing its phenoxyl radical. A significant part of NADH/PMQR-catalyzed reduction of CoQ0 (and Trolox recycling) was superoxide-dependent. Overall, our results demonstrate that PMQR in the model system used can act as an antioxidant enzyme that recycles water-soluble homologues of coenzyme Q and vitamin E.
authors.affiliation: Department of Environmental and Occupational Health, University of Pittsburgh, PA 15238, USA.
authors.forename: V E
authors.initials: VE
authors.lastname: Kagan
authors.forename: A
authors.initials: A
authors.lastname: Arroyo
authors.forename: V A
authors.initials: VA
authors.lastname: Tyurin
authors.forename: Y Y
authors.initials: YY
authors.lastname: Tyurina
authors.forename: J M
authors.initials: JM
authors.lastname: Villalba
authors.forename: P
authors.initials: P
authors.lastname: Navas
mesh_terms: D000818:Animals; D016227:Benzoquinones / Q000378:metabolism*; D002384:Catalysis; D002462:Cell Membrane; D002839:Chromans / Q000378:metabolism; D042967:Electron Transport Complex I; D019787:Linoleic Acid / Q000378:metabolism; D008084:Lipoxygenase / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D010084:Oxidation-Reduction; D010636:Phenols; D013481:Superoxides / Q000378:metabolism*; D013552:Swine; D014810:Vitamin E / Q000378:metabolism*
chemical_list: D016227:Benzoquinones; D002839:Chromans; D010636:Phenols; D013481:Superoxides; D014810:Vitamin E; C042329:phenoxy radical; C109863:ubiquinone-O; D019787:Linoleic Acid; D008084:Lipoxygenase; D009247:NADH, NADPH Oxidoreductases; D042967:Electron Transport Complex I; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid