adenosine mono-, di- and triphosphates (AMP, ADP, ATP)

adenosine mono-, di- and triphosphates (AMP, ADP, ATP)

molecules in which one, two or three phosphate groups are combined with the ribose unit of adenosine. ATP is the key energy currency of every living cell. It is synthesized anaerobically by glycolysis and aerobically by oxidative phosphorylation, and is hydrolysed to ADP and a phosphate ion ('inorganic phosphate', P_i) by the ATPases of myosin, membrane pumps and all other energy-requiring systems. Accumulation of ADP, and even more so of AMP, signifies ATP depletion and stimulates ATP resynthesis. See also creatine kinase ( fig ), phosphocreatine.