Adenosine triphosphate

In biochemistry, adenosine triphosphate (commonly called ATP) is the "molecular currency" of intracellular energy transfers. It is a means of storing and transporting chemical energy within the cell and a precursor for RNA formation. Chemically, adenosine triphosphate consists of the adenosine nucleotide (which is ribose sugar and adenine base) plus three phosphate groups.

Hydrolysis of the phosphate-phosphate bonds releases energy that can be used by a variety of enzymes, motor proteins[?], and transport proteins[?] to carry out the work of the cell. This hydrolysis yields free inorganic phosphate ion and adenosine diphosphate, which can be broken down further to another phosphate ion and adenosine monophosphate. ATP can also be broken down to adenosine monophosphate directly, with the formation of pyrophosphate. This last reaction has the advantage of being effectively irreversible[?] in aqueous solution.

ATP can be produced by various cellular processes, most typically by oxidative phosphorylation in mitochondria or photosynthesis in chloroplasts.

Living cells also have other "high-energy" nucleoside triphosphates, such as guanine triphosphate[?]. Energy can be easily transferred between them and ATP in reactions such as those catalyzed[?] by nucleoside diphosphokinase[?]:

ADP + GTP[?] ↔ ATP + GDP[?]

ATP is also one of the four building block molecules of RNA (ribonucleic acid).

There is talk of using ATP which is naturally present in human blood as a power source for nanotechnology and implants. Artificial pacemakers could become independent of batteries.

See also cyclic adenosine monophosphate, adenosine monophosphate, adenosine diphosphate, and phosphagens

External Link

• http://gened.emc.maricopa.edu/bio/bio181/BIOBK/BioBookATP