Proton electrochemical gradient and phosphate potential in mitochondria.
The paper reports an analysis of the relationship between deltamuH the proton electrochemical potential difference, and deltaGp, the phosphate potential. Depression of deltamuH and deltaGp has been obtained by titration with: (a) carbonylcyanide trifluoromethoxyphenylhydrazone; (b) nigericin (+ valinomycin); (c) KCl (+ valinomycin); and (d) rotenone. The uncoupler depresses deltamuH more than nigericin (+ valinomycin), KCl (+ valinomycin) and rotenone at equivalent deltaGp. The deltaGp/deltamuH ratio is about 3 at high values of deltamuH. When deltaGp and deltamuH are depressed by nigericin (4 valinomycin) the deltaGp/deltamuH ratio remains constant. When deltaGp and deltamuH are depressed by uncouplers, the deltaGp/deltamuH ratio increases hyperbolically tending to infinity while deltamuH tends to zero. The absence of constant proportionality between deltaGp and deltamuH indicates that the proton gradients driving ATP synthesis presumably operate within microscopic environments.
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000818:Animals; D001693:Biological Transport, Active; D004579:Electron Transport / Q000187:drug effects; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008930:Mitochondria, Liver / Q000502:physiology*; D010710:Phosphates / Q000378:metabolism*; D011522:Protons; D051381:Rats; D013816:Thermodynamics; D014475:Uncoupling Agents / Q000494:pharmacology
D010710:Phosphates; D011522:Protons; D014475:Uncoupling Agents; D000255:Adenosine Triphosphate