Generation of Membrane Potential by Cytochrome bd

An overview of current notions on the mechanism of generation of a transmembrane electric potential difference (Δψ) during the catalytic cycle of a bd -type triheme terminal quinol oxidase is presented in this work. It is suggested that the main contribution to Δψ formation is made by the movement of H + across the membrane along the intra-protein hydrophilic proton-conducting pathway from the cytoplasm to the active site for oxygen reduction of this bacterial enzyme.