title: Detection of catalase in rat heart mitochondria.
abstract: The presence of heme-containing catalase in rat heart mitochondria (20 +/- 5 units/mg) was demonstrated by biochemical and immunocytochemical analysis. Intact rat heart mitochondria efficiently consumed exogenously added H2O2. The rate of H2O2 consumption was not influenced by succinate, glutamate/malate, or N-ethylmaleimide but was significantly inhibited by cyanide. Hydrogen peroxide decomposition by mitochondria yielded molecular oxygen in a 2:1 stoichiometry, consistent with a catalytic mechanism. Mitochondrial fractionation studies and quantitative electron microscopic immunocytochemistry revealed that most catalase was matrix-associated. Electrophoretic analysis and Western blotting of the mitochondrial matrix fraction indicated the presence of a protein with similar electrophoretic mobility to bovine and rat liver catalase and immunoreactive to anti-catalase antibody. Myocardial tissue has a lower catalase-specific activity and a greater mitochondrial H2O2 production/g of tissue than most organs. Thus catalase, representing 0.025% of heart mitochondrial protein, is important for detoxifying mitochondrial derived H2O2 and represents a key antioxidant defense mechanism for myocardial tissue.
authors.affiliation: Department of Anesthesiology, University of Alabama, Birmingham 35233.
authors.forename: R
authors.initials: R
authors.lastname: Radi
authors.forename: J F
authors.initials: JF
authors.lastname: Turrens
authors.forename: L Y
authors.initials: LY
authors.lastname: Chang
authors.forename: K M
authors.initials: KM
authors.lastname: Bush
authors.forename: J D
authors.initials: JD
authors.lastname: Crapo
authors.forename: B A
authors.initials: BA
authors.lastname: Freeman
mesh_terms: D000818:Animals; D002374:Catalase / Q000032:analysis / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007150:Immunohistochemistry; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008168:Lung / Q000201:enzymology / Q000648:ultrastructure; D008830:Microbodies / Q000201:enzymology; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000201:enzymology / Q000648:ultrastructure; D008929:Mitochondria, Heart / Q000201:enzymology* / Q000648:ultrastructure; D008954:Models, Biological; D008970:Molecular Weight; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D051381:Rats
chemical_list: D006861:Hydrogen Peroxide; D002374:Catalase; D003576:Electron Transport Complex IV