ATP syntase

ATP synthase is a ubiquitous membrane enzyme that plays a key role in biological energy metabolism. This enzyme interconverts two major "energy currencies" of a living cell: adenosine triphosphate (ATP) and transmembrane electrochemical proton potential difference. ATP synthase is found in bacteria, plants, and animals. In most organisms the primary function of the enzyme is ATP synthesis from adenosine diphosphate (ADP) and inorganic phosphate (Pi). The energy needed for this process comes from the proton electrochemical potential difference generated by respiration or photosynthesis. The average daily turnover of ATP in human body exceeds 50 kg! And about 95% of this ATP is made by ATP synthase. In some bacteria, however, a reverse activity - namely, ATP-driven proton pumping - is of primary importance.