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 nucleic acid formation. Chemically, adenosine triphosphate is a nucleotide consisting of the nucleoside adenosine (which is ribose sugar and adenine base) plus three phosphate groups.
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Production
ATP can be produced by various cellular processes, most typically by oxidative phosphorylation in mitochondria or photosynthesis in chloroplasts.
Other triphosphates
Living cells also have other "high-energy" nucleoside triphosphates, such as guanine triphosphate. Between them and ATP, energy can be easily transferred with reactions such as those catalyzed by nucleoside diphosphokinase:
Energy is released when hydrolysis of the phosphate-phosphate bonds is carried out. This energy can be used by a variety of enzymes, motor proteins, and transport proteins to carry out the work of the cell. Also, the hydrolysis yields free inorganic phosphate 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.
Reaction of ADP with GTP
ATP is also one of the four building block molecules of RNA (ribonucleic acid) and DNA (deoxyribonucleic acid).
There is talk of using ATP 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
