Protonmotive functions of cytochrome c oxidase in reconstituted vesicles. Influence of turnover rate on ‘proton translocation’
- 15 January 1983
- journal article
- research article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 210 (1), 199-205
- https://doi.org/10.1042/bj2100199
Abstract
1. Oxidation of ferrocytochrome c by cytochrome c oxidase incorporated into proteoliposomes induces a transient acidification of the external medium. This change is dependent on the presence of valinomycin and can be abolished by carbonyl cyanide p-trifluoromethoxyphenylhydrazone or by nigericin. The H+/e- ratio for the initial acidification varies with the internal buffering capacity of the vesicles, and under suitable conditions approaches + 1, the pulse slowly decaying to give a net alkalinity change with H+/e- value approaching −1. 2. Inhibition of cytochrome c oxidase turnover by ferricytochrome c or by azide addition results in ferrocytochrome c-dependent H+ pulses with decreasing H+/e- ratios. The rate of the initial H+ production remains higher than the rate of equilibration of the pH gradient, indicating an intrinsic dependence of the H+/e- ratio on enzyme turnover. The final net alkalinity changes are relatively unaffected by turnover inhibition.This publication has 28 references indexed in Scilit:
- Inhibition of cytochrome c oxidase function by dicyclohexylcarbodiimideBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1981
- Proton-pumping cytochrome c oxidaseBiochimica et Biophysica Acta (BBA) - Reviews on Bioenergetics, 1979
- Turnover and vectorial properties of cytochrome c oxidase in reconstituted vesiclesBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1979
- Unequal charge separation by different coupling spans of the mitochondrial electron transport chainFEBS Letters, 1978
- Proton-translocating cytochrome c oxidase in artificial phospholipid vesiclesBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1978
- The Proton Pump of Cytochrome c Oxidase and Its StoichiometryEuropean Journal of Biochemistry, 1978
- Steady state spectra of cytochromecoxidase in reconstituted vesiclesFEBS Letters, 1978
- Measurements of the components of the protonmotive force generated by cytochrome oxidase in submitochondrial particlesFEBS Letters, 1978
- Cytochrome c oxidase is not a proton pumpFEBS Letters, 1978
- The mechanism of energy conservation and transduction by mitochondrial cytochrome c oxidaseBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1977