The markers of pig heart mitochondrial sub-fractions : I. - The dual location of NADPH-cytochrome c reductase in outer membrane and microsomes.
Biochimie, 1978;60(11-12):1289-98.
PMID: 223663
Impact factor: 4.372
Abstract
Evidence is presented about the dual location of NADPH-cytochrome c reductase in mitochondrial outer membranes as well as in microsomes, from pig heart. A high specific activity, was found in both fractions, even after their purification by washing, digitonin treatments, or passages on sucrose gradients. A large fraction of the total activity was associated with both mitochondria and microsomes. Mitochondrial outer membrane differs from microsomes by a low choline phosphotransferase activity and the absence of cytochrome P-450. The properties of mitochondrial and microsomal rotenone-insensitive NADH- and NADPH-cytochrome c reductases were studied. In microsomes, both activities have the same optimum pH (8.5) ; in contrast, in mitochondria they have a different one. The Km-NADPH were always much higher than those for NADH. In mitochondria the Km for NAD(P)H were dependent on cytochrome c concentration. The results show that the rotenone-insensitive NADH- and NADPH-cytochrome c reductases of mitochondria and microsomes have quite different behavior and do not appear to be supported by the same enzyme.
MeSH terms
Animals; Cell Fractionation; Cytochrome P-450 Enzyme System; Cytochrome Reductases; Diacylglycerol Cholinephosphotransferase; Intracellular Membranes; Kinetics; Microsomes; Mitochondria, Heart; Myocardium; NAD; NADPH-Ferrihemoprotein Reductase; Swine
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