[A three-cycle mechanism of the respiratory chain].
A scheme of the respiratory chain is presented, according to which three delta mu H-generators (complexes I, III and IV) provide for the transmembrane transport of ten H+ ions per atom of adsorbed O2. It is assumed that all the three delta mu H-generators operate in accordance with the same mechanism, namely, they translocate electrons at a distance averaging 1/2 of membrane width, whereas protons moving in the opposite direction pass the other halfwidth across the membrane. A redox cycle functions in each of the three sites of the energy coupling mechanism: the flavin (F) cycle in complex I, the Q-cycle in complex III and the O-cycle in complex IV. These cycles are interconnected by mobile carriers: the F- and Q-cycles by ubiquinone and the Q- and O-cycles by cytochrome c.
D000818:Animals; D003574:Cytochrome c Group / Q000378:metabolism; D004579:Electron Transport; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D008954:Models, Biological; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D014451:Ubiquinone / Q000378:metabolism
D003574:Cytochrome c Group; D014451:Ubiquinone
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