ATP Synthase

The production of ATP from ADP and inorganic phosphate using the energy from the proton gradient across the inner membrane of the mitochondria is called chemiosmosis.ATP synthase is a proton channel. The molecule has three identical subunits and a gamma subunit. As H⁺ ions pass through the hydrophilic pore the gamma subunit rotates, causing each of the three subunits in turn to go through three conformational changes. About three H⁺ ions are needed for each ATP made. The first allows the binding of ADP and inorganic phosphate. The second causes ATP to be produced and the third causes ATP to be released from the binding site.