Thermodynamic limits to the stoichiometry of H+ pumping by mitochondrial cytochrome oxidase

FEBS Letters

Brand, M.D.¹  Brown, G.C.¹  Murphy, M.P.¹ 

[1]Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, England

关键词: Cytochrome oxidase Proton pumping H+/O stoichiometry Thermodynamics Mitochondria;    H+/O;    number of protons pumped from the matrix to the external phase per pair of electrons passed through cytochrome oxidase;    q +/O;    net number of positive charges translocated outwards across the inner mitochondrial membrane per pair of electrons passed through cytochrome oxidase;    Δs̄mH+;    external proton electrochemical potential - intramitochondrial proton electrochemical potential;    ΔΨ;    external electrical potential - intramitochondrial electrical potential;    ΔpH;    external pH - intramitochondrial pH;    J o;    rate of oxygen consumption;    E m;    midpoint potential;    E h;    actual redox potential;    ΔG;    Gibbs free energy difference;    TPMP;    methyltriphenylphosphonium;    FCCP;    carbonyl cyanide p-trifluoromethoxyphenylhydrazone;    TMPD;    N;    N;    N';    N'-tetramethyl-p-phenylenediamine;   

DOI  :  10.1016/0014-5793(85)81204-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

H⁺/O stoichiometries of 0, 2 and 4 have been proposed for cytochrome oxidase. Here we show that a stoichiometry of 4 is thermodynamically impossible for rat liver cytochrome oxidase under normal conditions.

【 授权许可】

Unknown