Coupled proton and electron transfer reactions in cytochrome oxidase

10.2741/1237 ◽  
2004 ◽  
Vol 9 (1-3) ◽  
pp. 581 ◽  
Author(s):  
Robert, B. Gennis
Keyword(s):  
Electron Transfer ◽  
Cytochrome Oxidase ◽  
Transfer Reactions ◽  
Electron Transfer Reactions

ELECTRON TRANSFER REACTIONS COUPLED TO PROTON TRANSLOCATION: CYTOCHROME OXIDASE, PROTON PUMPS, AND BIOLOGICAL ENERGY TRANSDUCTION

2003 ◽  
Vol 02 (01) ◽  
pp. 91-118 ◽  
Author(s):  
ALEXEI A. STUCHEBRUKHOV
Keyword(s):  
Electron Transfer ◽  
Oxygen Reduction ◽  
Cytochrome Oxidase ◽  
Molecular Mechanisms ◽  
Proton Gradient ◽  
Transfer Reactions ◽  
Proton Pumps ◽  
Main Question ◽  
Long Distance ◽  
Electron Transfer Reactions

Cytochrome oxidase (COX) is the terminal component of electron transport chain of the respiratory system in mitochondria, and one of the key enzymes responsible for energy generation in cells. COX functions as a proton pump that utilizes free energy of oxygen reduction for translocation of protons across the mitochondrion membrane. The proton gradient created in the process is later utilized to drive synthesis of ATP. Although the structure of COX has been recently resolved, the molecular mechanism of proton pumping remains unknown. In this paper, general principles and possible molecular mechanisms of energy transformations in this enzyme will be discussed. The main question is how exactly chemical energy of oxygen reduction and water formation is transformed into a proton gradient; or, how exactly electron transfer reactions are utilized to translocate protons across the mitochondrion membrane against the electrochemical gradient. A key to the solution of this problem is in understanding correlated transport of electrons and protons. Here, theoretical models are discussed for coupled electron and proton transfer reactions in which an electron is tunneling over long distance between two redox cofactors, and a coupled proton is moving along a proton conducting channel in a classical, diffusion-like random walk fashion. Such reactions are typical for COX and other enzymes involved in biological energy transformations.

ELECTRON TRANSFER REACTIONS IN CYTOCHROME OXIDASE

1979 ◽  
pp. 483-511 ◽  
Author(s):  
Britton Chance ◽  
Carlo Saronio ◽  
John S. Leigh ◽  
Alan Waring
Keyword(s):  
Electron Transfer ◽  
Cytochrome Oxidase ◽  
Transfer Reactions ◽  
Electron Transfer Reactions
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