The H+/e− stoicheiometry of respiration-linked proton translocation in the cytochrome system of mitochondria

摘要: 1. The →H+/e− quotients for proton release from mitochondria associated with electron flow succinate and duroquinol to O2, ferricyanide or ferricytochrome c, NNN′N′-tetramethyl-p-phenylenediamine+ascorbate were determined rate measurements of translocation. 2. Care was taken avoid, take into account, unrelated translocation, which might place in addition the oxido-reductions that subject our analysis. Spectrophotometric techniques chosen provide accurate measurement consumption oxidants reductants. translocation measured fast pH meters a precision 10−3 unit. 3. →H+/O quotient oxidation was, at neutral pH, 4, when computed on basis spectrophotometric determinations O2 oxidation. Higher oxidation, obtained polarographic consumption, resulted underestimation respiratory rate. 4. →H+/2e− c ranged 3.9 3.6. 5. Respiration elicited by antimycin-inhibited extra produced ascorbate dehydroascorbate. Accurate respiration showed ratio only 0.25 not 0.7–1.0 as inadequate assay respiration. Proton practically suppressed preincubated aerobically absence antimycin. Furthermore, scalar water production lower than expected stoicheiometry. Thus observed during is caused endogenous hydrogenated 6. It concluded (i) cytochrome system is, 4 6 8 reported others; (ii) all four protons are released quinol c; (iii) oxidase transfers electrons matrix aqueous phase does pump outer phase.