Oxidation of NADH via an "external" pathway in skeletal-muscle mitochondria and its possible role in the repayment of lactacid oxygen debt.
Mitochondria isolated from skeletal muscle of rat catalyse oxidation of the external NADH (in the presence of rotenone, antimycin A and cytochrome c) at a rate of 15 natoms O2/min/mg protein by a pathway sensitive to mersalyl. In a medium supplemented with commercial lactate dehydrogenase, or when mitochondria were incubated in the presence of a cytoplasm, the NADH oxidation could be arrested by pyruvate. The inhibitory effect of pyruvate could be released by lactate. In the presence of NAD and cytochrome c, the reconstructed system containing skeletal muscle mitochondria plus cytoplasmic fraction was active in oxidation of L-lactate despite of the presence of rotenone and antimycin A. The lactate oxidation was sensitive to mersalyl and cyanide.
D000818:Animals; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007773:Lactates / Q000378:metabolism*; D019344:Lactic Acid; D008634:Mersalyl / Q000494:pharmacology; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D009245:NADH Dehydrogenase / Q000378:metabolism; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D051381:Rats; D012402:Rotenone / Q000494:pharmacology
D007773:Lactates; D012402:Rotenone; D009243:NAD; D019344:Lactic Acid; D008634:Mersalyl; D007770:L-Lactate Dehydrogenase; D009245:NADH Dehydrogenase