Detection of catalase in rat heart mitochondria.
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.
Radi
R
R
Department of Anesthesiology, University of Alabama, Birmingham 35233.
Turrens
J F
JF
Chang
L Y
LY
Bush
K M
KM
Crapo
J D
JD
Freeman
B A
BA
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
D006861:Hydrogen Peroxide; D002374:Catalase; D003576:Electron Transport Complex IV