Kinetics of proton pumping in cytochrome c oxidase.
We propose a simple model of cytochrome c oxidase, including four redox centers and four protonable sites, to study the time evolution of electrostatically coupled electron and proton transfers initiated by the injection of a single electron into the enzyme. We derive a system of master equations for electron and proton state probabilities and show that an efficient pumping of protons across the membrane can be obtained for a reasonable set of parameters. All four experimentally observed kinetic phases appear naturally from our model. We also calculate the dependence of the pumping efficiency on the transmembrane voltage at different temperatures and discuss a possible mechanism of the redox-driven proton translocation.
Smirnov
Anatoly Yu
AY
Advanced Science Institute, The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-0198, Japan. asmirnov@rogers.com
Mourokh
Lev G
LG
Nori
Franco
F
D003198:Computer Simulation; D003576:Electron Transport Complex IV / Q000378:metabolism*; D007700:Kinetics; D008954:Models, Biological; D010084:Oxidation-Reduction; D017494:Proton Pumps / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
D017494:Proton Pumps; D003576:Electron Transport Complex IV