title: Proton/electron stoichiometry of mitochondrial complex I estimated from the equilibrium thermodynamic force ratio.
abstract: The thermodynamic forces on electrons (delta Eh) and protons (delta p) across mitochondrial complexes I, III and IV were measured in isolated mitochondria respiring on succinate. The force ratio (delta Eh/delta p) across complex I close to equilibrium was found to be about 2. The equilibrium force ratio across complex I was measured during sulphite oxidation and was again close to 2. These results indicate that the proton/electron stoichiometry of complex I is 2, in conditions of high protonmotive force.
authors.affiliation: Department of Biochemistry, University of Cambridge, U.K.
authors.forename: G C
authors.initials: GC
authors.lastname: Brown
authors.forename: M D
authors.initials: MD
authors.lastname: Brand
mesh_terms: D020155:3-Hydroxybutyric Acid; D000090:Acetoacetates / Q000378:metabolism; D000818:Animals; D004579:Electron Transport; D014450:Electron Transport Complex III / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D005260:Female; D006885:Hydroxybutyrates / Q000378:metabolism; D008564:Membrane Potentials; D008930:Mitochondria, Liver / Q000201:enzymology*; D016660:NAD(P)H Dehydrogenase (Quinone); D010084:Oxidation-Reduction; D011522:Protons; D011808:Quinone Reductases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013053:Spectrophotometry; D013386:Succinates / Q000378:metabolism; D019802:Succinic Acid; D013447:Sulfites / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D000090:Acetoacetates; D006885:Hydroxybutyrates; D011522:Protons; D013386:Succinates; D013447:Sulfites; C016635:acetoacetic acid; D019802:Succinic Acid; D016660:NAD(P)H Dehydrogenase (Quinone); D011808:Quinone Reductases; D003576:Electron Transport Complex IV; D014450:Electron Transport Complex III; D020155:3-Hydroxybutyric Acid