New insights on the cytochrome c oxidase proton pump.
Cytochrome c oxidase vesicles were used to show that, under appropriate experimental conditions: (1) no net deprotonation of the vesicular membrane or of the incorporated enzyme occurs during the oxidation of ferrocytochrome c; (2) the pH equilibration kinetics of a respiration-induced pH gradient across the bilayer are a simple function of the ohmic proton-conductance properties of the membrane; (3) a fairly constant stoichiometry (0.8-0.7) of the numbers of protons pumped per molecule of ferrocytochrome c oxidized, i.e. the H+/e- ratio, over a wide range of dioxygen molecules reduced (1-12) is observed.
Thelen
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O'Shea
P S
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Azzi
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D003956:Dialysis; D003576:Electron Transport Complex IV / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010084:Oxidation-Reduction; D011199:Potentiometry; D011522:Protons
D011522:Protons; D003576:Electron Transport Complex IV