title: Relative metabolism of quinones to semiquinone radicals in xanthine oxidase system.
abstract: Rates of enzymatic single-electron reduction of some myotoxic quinones to semiquinone metabolites in an in vitro xanthine oxidase/hypoxanthine/catalase system varied widely. Naphthoquinones, especially juglone, were found to undergo rapid single-electron reduction. Benzoquinones and benzoquinoneimines, as well as phenanthrene-9,10-quinone, benzo[a]pyrene-3,6-quinone, and diethylstilbestrolquinone, were also actively reduced. The anthraquinones danthron, doxorubicin and emodin were poorly metabolized in this system. N-Acetylcysteine inhibited quinone-stimulated cytochrome C reduction at high concentrations. The results of this study are discussed with respect to cytotoxicity and mutagenicity of selected quinones.
authors.affiliation: Department of Environmental Toxicology, University of California, Davis 95616.
authors.forename: D C
authors.initials: DC
authors.lastname: Lewis
authors.forename: T
authors.initials: T
authors.lastname: Shibamoto
mesh_terms: D000433:1-Propanol / Q000494:pharmacology; D000111:Acetylcysteine / Q000494:pharmacology; D000880:Anthraquinones / Q000378:metabolism; D016227:Benzoquinones; D003574:Cytochrome c Group / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology; D009285:Naphthoquinones / Q000378:metabolism; D010084:Oxidation-Reduction; D011809:Quinones / Q000378:metabolism*; D014969:Xanthine Oxidase / Q000378:metabolism*
chemical_list: D000880:Anthraquinones; D016227:Benzoquinones; D003574:Cytochrome c Group; D009285:Naphthoquinones; D011809:Quinones; C025232:semiquinone radicals; D000431:Ethanol; C004532:quinone; D000433:1-Propanol; D014969:Xanthine Oxidase; D000111:Acetylcysteine