title: Oxidation of Cu(I)-thionein by enzymically generated H2O2.
abstract: Very little is known of the metabolism of copper on a molecular level. For example, there is no evidence of an oxidative breakdown of Cu(I)-thionein leading to Cu(II). Thus it was of interest to use L- and D-amino-acid oxidases, amino oxidase and galactose oxidase to control the oxidation of Cu(I)-thionein by enzymically generated H2O2. In the presence of these enzymes Cu(II) was generated in each case. In a more detailed study the Cu(I)-thiolate chromophores of Cu-thionein were oxidized in the presence of xanthine oxidase as deduced from spectrometrical measurements using EPR and circular dichroism. Unlike Cu2Zn2-superoxide dismutase catalase inhibited the oxidative cleavage, suggesting peroxide as the actual oxidizing agent. Possibly there is an enzymic oxidative pathway for the generation of biologically important Cu(II).
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism; D002417:Cattle; D006861:Hydrogen Peroxide / Q000378:metabolism*; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism; D008668:Metallothionein / Q000378:metabolism*; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D014969:Xanthine Oxidase / Q000378:metabolism; D015003:Yeasts / Q000378:metabolism
chemical_list: C007121:copper thionein; D008668:Metallothionein; D006861:Hydrogen Peroxide; D002374:Catalase; D014969:Xanthine Oxidase