Adenosine triphosphate (ATP) is an adenine mononucleotide with three phosphate groups, each of which is connected to one another by an anhydride bond. ATP is the central molecule for the transmission of energy in the organism.

The energy is primarily tied up in the anhydride bond of the beta phosphate residue to the gamma phosphate residue. When a phosphate residue is removed to form adenosine diphosphate, energy is released. This energy is then used for energy-consuming processes. As a nucleotide, ATP consists of the purine base adenine, the sugar ribose, and three phosphate residues. There is a glycosidic bond between adenine and ribose. Furthermore, the alpha phosphate residue is linked to the ribose by an ester bond.

There is an anhydride bond between alpha, beta and gamma phosphate. After the removal of two phosphates, the nucleotide adenosine monophosphate (AMP) is formed. This molecule is an important building block of RNA.

Function, effect & tasks

Adenosine triphosphate has a variety of functions in the organism. Its main function is to store and transmit energy. All processes in the body are associated with energy transfers and energy conversions. The organism has to do chemical, osmotic or mechanical work. ATP quickly provides energy for all these processes. 

ATP is a short-term energy store, which is used up quickly and therefore has to be synthesized again and again. The largest part of the energy-consuming processes are transport processes within the cell and out of the cell. Biomolecules are transported to the sites of their reaction and conversion. Anabolic processes such as protein synthesis or the formation of body fat also require ATP as an energy-transmitting agent. Molecular transport across the cell membrane or the membranes of various cell organelles is also energy dependent.

Furthermore, the mechanical energy for muscle contractions can only be provided by the action of ATP from energy-yielding processes. In addition to its function as an energy carrier, ATP is also an important signaling molecule. It acts as a co-substrate for the so-called kinases. Kinases are enzymes that transfer phosphate groups to other molecules. These are mainly protein kinases, which influence the activity of various enzymes by phosphorylation. Extracellularly, ATP is an agonist of receptors of cells in the peripheral and central nervous system .

It thus participates in the regulation of blood circulation and the triggering of inflammatory reactions. In the case of injuries to the nerve tissue, it is increasingly released in order to mediate the increased formation of astrocytes and neurons .

Formation, Occurrence, Properties & Optimal Values

Adenosine triphosphate is only a short-term store of energy and is used up within a few seconds in energy-consuming processes. Therefore, its constant regeneration is a vital task. The molecule plays such a central role that ATP with a mass of half the body weight is produced within a day. In the process, adenosine diphosphate is converted into adenosine triphosphate by an additional bond with phosphate, using energy, which immediately supplies energy again by splitting off the phosphate and converting it back into ADP.

Two different reaction principles are available for the regeneration of ATP. One principle is substrate level phosphorylation. In this reaction, in an energy-yielding process, a phosphate residue is directly transferred to an intermediate molecule, which is immediately passed to ADP to form ATP. A second reaction principle is part of the respiratory chain as electron transport phosphorylation . This reaction only takes place in the mitochondria . As part of this process, an electrical potential is built up across the membrane via various proton-transporting reactions.

The reverse flow of protons results in the formation of ATP from ADP with the release of energy. This reaction is catalyzed by the enzyme ATP synthetase. Overall, these regeneration processes are still too slow for some requirements. During muscle contraction, all stores of ATP are used up after two to three seconds. For this purpose, energy-rich creatine phosphate is available in muscle cells, which immediately makes its phosphate available for the formation of ATP from ADP. This supply is now exhausted after six to ten seconds. After that, the general regeneration processes must come into play again. However, due to the effect of creatine phosphate, it is possible to extend muscle training a little without premature exhaustion.

Diseases & Disorders

When too little adenosine triphosphate is produced, states of exhaustion occur. ATP is mainly synthesized in the mitochondria via electron transport phosphorylation. When the mitochondrial function is disrupted, the production of ATP is also reduced.

Studies have shown that patients with chronic fatigue syndrome (CFS) have a reduced ATP concentration. This reduced production of ATP always correlated with disorders in the mitochondria (mitochondriopathies). The causes of the mitochondriopathies included cellular hypoxia , EBV infections , fibromyalgia or chronic degenerative inflammatory processes. There are both genetic and acquired mitochondrial disorders. Around 150 different diseases have been described that lead to mitochondrial disease.

These include diabetes mellitus , allergies , autoimmune diseases , dementia , chronic inflammation or immune deficiency diseases . The states of exhaustion associated with these diseases are caused by a lower supply of energy due to the reduced production of ATP. As a result, disorders of mitochondrial function can lead to multi-organ diseases.