Researchers at the Institute of Biotechnology of the University of Helsinki have for the first time identified an internal electron transfer reaction that initiates the proton pump mechanism of the respiratory enzyme. These new results are published in the Thursday (April 6th) issue of Nature.
The functions of the lungs, the blood circulation, and the red blood cells in respiration are only an overture to the physicochemical reaction in the cells where oxygen is reduced to water. Oxygen consumption in cell respiration is a strictly controlled enzymatic reaction in the inner mitochondrial membrane. The respiratory enzyme cytochrome oxidase functions as a proton pump that transduces free energy from oxygen reduction to an electrochemical proton gradient, which is utilised by another enzyme to produce ATP, the cells' general energy currency.
The results by the research group of academy professor Mårten Wikstrom revealed the coupling between the function of the proton pump and oxygen reduction: an internal electron transfer initiates the first stage of the pump mechanism. "This finding opens the door towards understanding the mechanism, which has been the subject of research for almost 30 years", Wikstrom says.