ATP synthase is a general term for an enzyme that can synthesize adenosine triphosphate from adenosine diphosphate and inorganic phosphate by using some form of energy. This energy is often in the form of protons moving down an electrochemical gradient, such as from the lumen into the stroma of chloroplasts or from the inter-membrane space into the matrix in mitochondria. The overall reaction sequence is :ADP + Pi ATP. These enzymes are of crucial importance in almost all organisms, because ATP is the common energy currency of cells.The antibiotic oligomycin inhibits the FO unit of ATP synthase