title: The interaction of cytochrome oxidase with hydrogen peroxide: the relationship of compounds P and F.
abstract: Upon reaction of cytochrome oxidase with hydrogen peroxide, the spectral changes are complete, with slightly less than 1 equiv of hydrogen peroxide per cytochrome oxidase. At pH 8 the product is a mixture of the P and F forms, while at pH 6 the product is exclusively the F form. These data are inconsistent with current interpretations of the structure of compounds P and F. Two stable radical species are detected by EPR; the relative amounts of these species are pH dependent. The MCD spectra of pure P and F are reported. It is suggested that compound F is a hydrogen peroxide adduct of cytochrome oxidase with cytochrome a3 in the low-spin state and that compound P is an oxyferryl state of cytochrome alpha 3 in support of the recent Raman data of Proshlyakov et al. [(1994) J. Biol. Chem. 269, 29385-29388]. We also suggest that copper B is in the trivalent state in compound P.
authors.affiliation: Department of Biochemistry & Cell Biology, Rice University, Houston, Texas 77251-1892, USA.
authors.forename: M
authors.initials: M
authors.lastname: Fabian
authors.forename: G
authors.initials: G
authors.lastname: Palmer
mesh_terms: D002248:Carbon Monoxide / Q000378:metabolism; D002942:Circular Dichroism; D003300:Copper / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000378:metabolism*; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000378:metabolism; D008956:Models, Chemical; D009580:Nitroblue Tetrazolium / Q000378:metabolism; D010084:Oxidation-Reduction; D013053:Spectrophotometry; D013481:Superoxides / Q000378:metabolism; D019820:Xanthine; D014969:Xanthine Oxidase / Q000378:metabolism; D014970:Xanthines / Q000378:metabolism
chemical_list: D005609:Free Radicals; D014970:Xanthines; D013481:Superoxides; D019820:Xanthine; D009580:Nitroblue Tetrazolium; D003300:Copper; D002248:Carbon Monoxide; D006861:Hydrogen Peroxide; D007501:Iron; D014969:Xanthine Oxidase; D003576:Electron Transport Complex IV