Adenosine triphosphate (ATP) is a complex organic chemical that provides #energy to drive many processes in living cells, e.g. muscle contraction, nerve impulse propagation, and chemical synthesis. Found in all forms of life, ATP is often referred to as the "molecular unit of currency" of intracellular energy transfer. When consumed in #metabolic processes, it converts either to adenosine diphosphate (ADP) or to adenosine #monophosphate (AMP). Other processes regenerate ATP so that the human #body recycles its own body #weight equivalent in ATP each day. It is also a precursor to DNA and RNA, and is used as a coenzyme.
From the perspective of biochemistry, ATP is classified as a #nucleoside triphosphate, which indicates that it consists of three components: a nitrogenous base (adenine), the sugar ribose, and the triphosphate.
In terms of its structure, ATP consists of an adenine attached by the 9-nitrogen atom to the 1′ carbon atom of a sugar (ribose), which in turn is attached at the 5′ carbon atom of the sugar to a triphosphate group. In its many reactions related to metabolism, the adenine and sugar groups remain unchanged, but the triphosphate is converted to di- and monophosphate, giving respectively the derivatives ADP and AMP. The three phosphoryl groups are referred to as the alpha (α), beta (β), and, for the terminal phosphate, gamma (γ). In neutral solution, ionized ATP exists mostly as ATP4−, with a small proportion of ATP3−. Salts of ATP can be isolated as colorless solids.
With a typical intracellular concentration of 1–10 mM, ATP is abundant. The dephosphorylation of ATP and rephosphorylation of ADP and AMP occur repeatedly in the course of aerobic metabolism.
ATP can be produced by a number of distinct cellular processes; the three main pathways in eukaryotes are (1) glycolysis, (2) the citric acid cycle/oxidative phosphorylation, and (3) beta-oxidation. The overall process of oxidizing glucose to carbon dioxide, the combination of pathways 1 and 2, is known as cellular respiration, produces about 30 equivalents of ATP from each molecule of #glucose. #jeralabs