title: Cytochrome oxidase activity of mitochondria from ischemic and reperfused myocardium.
abstract: Polarographic measurements show that activity of cytochrome oxidase (CO), assayed as ascorbate plus TMPD oxidase, is decreased in the mitochondria (M) from postischemic areas of rabbit heart 1, 6, and 9 days after temporary (1-hr) coronary artery occlusion (CAO). This effect is observable only in the absence of added cytochrome c. Cytochrome oxidase activity in the cytochrome c-containing medium was not different from the control level. Levels of cytochromes c + c1 and a were substantially lower in tissue from postischemic areas and elevated in the intact tissue 1 and 6 days after temporary CAO as compared with control hearts. Stoichiometry of the cytochromes was not changed. After 1 or 4 hr of permanent CAO, CO activity (plus cytochrome c) of ischemic M was equal to that of M from intact area; CO activity (with or without cytochrome c) was reduced after 0.5 and 1 hr but elevated after 3 or 4 hr of in vitro ischemia as compared with control. The changes of CO activity in infarcted human heart M were similar to those in rabbits after temporary CAO; CO activity was restored after addition of cytochrome c. The data suggest that leakage of cytochrome c occurs during isolation of M and is more pronounced in ischemia-damaged M.
mesh_terms: D000818:Animals; D003327:Coronary Disease / Q000201:enzymology*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D008929:Mitochondria, Heart / Q000201:enzymology*; D011817:Rabbits; D013938:Thymidine Monophosphate / Q000378:metabolism
chemical_list: D013938:Thymidine Monophosphate; D003576:Electron Transport Complex IV