ATP

Synonyms

Adenosine triphosphate; pppA

Definition

ATP is one of the four activated nucleotides incorporated into RNA by RNA polymerases. It is also extremely important in biochemistry as a high-energy molecule that releases the energy needed for many metabolic reactions by coupling hydrolysis into ADP and inorganic phosphate, or AMP and pyrophosphate, with various synthetic and mechanical processes. The formation of ATP in living organisms takes place through two main biochemical pathways, substrate-level phosphorylation (in which phosphate is transferred to ADP from activated phosphorylated intermediates) and membrane-associated processes (found in respiration and photosynthesis). Although prebiotic phosphorylation may have led to ATP from adenosine, ATP is usually not considered to have been abundant in prebiotic environments, and polyphosphates have been proposed as alternative primordial energy carriers.

See Also

• Adenine

• Nucleotide

• RNA