Adenosine triphosphate

Article

July 5, 2022

Adenosine triphosphate (lat. Adenosinum triphosphatum (ATP — ATP)) is a nucleotide known in biochemistry as "molecular currency" for intracellular energy transfer; that is, ATP is able to store and transport energy within cells. ATP also plays an important role in the synthesis of nucleic acids. ATP molecules are also used to store useful energy that plants convert in cellular respiration.

Chemical properties

Chemically, ATP consists of adenosine and three phosphate groups (triphosphate). Its empirical formula is C10H16N5O13P3, and its rational formula is C10H8N4O2NH2(OH)2(PO3H)3H, with a molecular weight of 507,184 u. Phosphorylation groups starting with that on AMP are called alpha (α), beta (ß), and gamma (γ) phosphates. The biochemical names for ATP are 9-ß-D-ribofuranosyladenine-5'-triphosphate, and equivalently, 9-ß-D-ribofuranosyl-6-amino-purine-5'-triphosphate.

Synthesis

ATP can be produced in various cellular processes, but most often in mitochondria by oxidative phosphorylation under the catalytic influence of ATP synthase or in the case of plants in chloroplasts, by photosynthesis. The main fuel for ATP synthesis is glucose and fatty acids. First, glucose is separated into pyruvate and cytosol. Two molecules of ATP are generated from each molecule of glucose. The final steps in ATP synthesis are performed in the mitochondria, and can generate up to 36 ATP.

ATP in the human body

The total amount of ATP in the human body is about 0.1 mole. The energy used by human cells requires the hydrolysis of 200 to 300 moles of ATP per day. This means that each ATP molecule is recycled 2000 to 3000 times each day. ATP cannot be stored, so its consumption must follow shortly after synthesis.

Other triphosphates

Living cells have other "high-energy" nucleoside triphosphates, such as guanosine triphosphate. Between them and ATP, energy can easily be transferred by reactions such as those catalyzed by nucleoside diphosphokinase: energy is released when the hydrolysis of phosphate-phosphate bonds is performed. This energy can be used by various enzymes, motor proteins, and transport proteins to carry out work in the cell. The process of hydrolysis releases inorganic phosphate and adenosine diphosphate, which can be further broken down into another phosphate ion and adenosine monophosphate. ATP can be broken down in adenosis�