ATP synthetase

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ATP synthetase (ATP synthase; F0F1 complex) An enzyme complex that catalyses the formation of ATP from ADP and inorganic phosphate. It occurs in the inner mitochondrial membrane and is responsible for oxidative phosphorylation during respiration. It is also found in the thylakoid membranes of chloroplasts, where it generates ATP in the light-dependent reactions of photosynthesis. Hence, ATP synthetase is of fundamental importance to the vast majority of living organisms. The synthetase complex consists of a membrane-spanning proton channel (the F0 portion) and an ATP-synthesizing part (the F1 portion). According to the chemiosmotic theory, protons (H+) flowing through the F0 channel provide the energy for phosphorylation of ADP at catalytic sites in the F1 portion. It is thought that three protons must flow through for each molecule of ATP synthesized.