Mitochondrial oxygen affinity as a function of redox and phosphate potentials.
1. The conditions under which mitochondria might catalyse a net reversal of oxidative phosphorylation are analysed. 2. Rat-liver mitochondria, incubated under such conditions, show a strongly diminished affinity for oxygen. 3. The velocity of respiration under these conditions is a hyperbolic function of the oxygen concentration. 4. The K-m for oxygen is less than 0.1 muM at low phosphate potential, irrespective of substrate, and 1-3 muM under reversal conditions. 5. The observed kinetics can be accounted for in a simple mechanism for cytochrome oxidase action.
D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D001665:Binding Sites; D004579:Electron Transport; D007700:Kinetics; D008433:Mathematics; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D011199:Potentiometry; D051381:Rats
D000963:Antimetabolites; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate