An adenosine triphosphate molecule stores energy that is released and used by energy-consuming reactions, such as muscle contraction, transmission of nerve impulses and formation of other molecules. ATP is found in cells and is made from the breakdown of food. It is composed of oxygen, hydrogen, phosphorus and carbon atoms. The energy in an ATP molecule is locked within phosphate bonds, which hold its phosphate groups together.
The energy in ATP powers chemical activities, such as the exchange of solutes and waste products across cell membranes. Cell division and motility also depend on ATP. Energy is released from ATP through a process called hydrolysis, which is catalyzed by adenosine triphosphatase. Energy in ATP is also released in the form of heat to regulate body temperature. The process of hydrolysis releases inorganic phosphate and adenosine diphosphate (ADP).
Oxidation is the opposite of hydrolysis and involves the regeneration of ATP by combining ADP with inorganic phosphates. The formation of ATP also uses energy. Fats produce more energy than carbohydrates and proteins. This energy is harvested from food through the process of cellular respiration, which occurs in mitochondria. Scientists in the United States and Germany discovered ATP in 1929, but it was until 1941 that its role in storing and supplying energy was described by a biochemist known as Fritz Lipmann.