title: The reactions of horseradish peroxidase, lactoperoxidase, and myeloperoxidase with enzymatically generated superoxide.
abstract: The formation and decay of intermediate compounds of horseradish peroxidase, lactoperoxidase, and myeloperoxidase formed in the presence of the superoxide/hydrogen peroxide-generating xanthine/xanthine oxidase system has been studied by observation of spectral changes in both the Soret and visible spectral regions and both on millisecond and second time scales. It is tentatively concluded that in all cases compound III is formed in a two-step reaction of native enzyme with superoxide. The presence of superoxide dismutase completely inhibited compound III formation; the presence of catalase had no effect on the process. Spectral data which indicate differences in the decay of horseradish peroxidase compound III back to the native state in comparison with compounds III of lactoperoxidase and myeloperoxidase are also presented.
authors.affiliation: Department of Chemistry, University of Alberta, Edmonton, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Metodiewa
authors.forename: H B
authors.initials: HB
authors.lastname: Dunford
mesh_terms: D002374:Catalase / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology; D006735:Horseradish Peroxidase / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D007784:Lactoperoxidase / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism*; D013053:Spectrophotometry; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*; D019820:Xanthine; D014969:Xanthine Oxidase / Q000378:metabolism; D014970:Xanthines / Q000378:metabolism
chemical_list: D014970:Xanthines; D013481:Superoxides; D019820:Xanthine; D003300:Copper; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; D007784:Lactoperoxidase; D010544:Peroxidases; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; D014969:Xanthine Oxidase