Experimental discrimination between proton leak and redox slip during mitochondrial electron transport.
By measuring the relationship between protonmotive force and the increment in oxygen consumption by mitochondria treated with submaximal amounts of uncoupler, we have experimentally tested four different models of imperfect coupling of oxidative phosphorylation. The results show that the increased rate of oxygen consumption at high protonmotive force is explained entirely by the dependence on protonmotive force of the passive proton leak conductance of the mitochondrial inner membrane. There is no measurable contribution from redox-slip reactions in the proton pumps caused by high protonmotive force. Neither is there any contribution from increased proton conductance of the membrane or increased redox slip in the respiratory chain caused by high turnover rates of the complexes.
Brand
M D
MD
Department of Biochemistry, University of Cambridge, U.K.
Chien
L F
LF
Diolez
P
P
D000818:Animals; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D004579:Electron Transport; D006863:Hydrogen-Ion Concentration; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D010101:Oxygen Consumption; D017494:Proton Pumps / Q000502:physiology; D011522:Protons; D051381:Rats
D017494:Proton Pumps; D011522:Protons; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone