| Abstract: | The correlation between deltamuH, the proton electrochemical potential difference, and the rate of controlled respiration is analyzed. deltamuH (the proton concentration gradient) is measured on the distribution of 3H]acetate, and deltapsi (the membrane potential) on the distribution of 86Rb+, 45Ca2+ and 3H]triphenylmethylphosphonium used either alone or simultaneously. The effects of the addition of ADP + hexokinase (state-3 ADP) and of carbonylcyanide trifluoromethoxyphenylhydrazone (state-3 uncoupler) on respiration and deltamuH are not equivalent: the uncoupler depresses deltamuH more than ADP at equivalent respiratory rates. The effects of the additions of nigericin-valinomycin and of ionophore A23187 (state-3 cation transport) and of carbonylcyanide trifluoromethoxy-phenylhydrazone (state 3-uncoupler) on respiration and deltamuH are also not equivalent: the uncoupler depresses deltamuH more than A23187 and nigericin + valinomycin at equivalent respiratory rate. A23187 is very efficient in stimulating respiration with negligible deltamuH changes. |
