Adenosine monophosphate (AMP), also known as 5'-adenylic acid, is a nucleotide. AMP consists of a phosphate group, the sugar ribose, and the nucleobase adenine; it is an ester of phosphoric acid and the nucleoside adenosine.[1] As a substituent it takes the form of the prefix adenylyl-.[2]
AMP plays an important role in many cellular metabolic processes, being interconverted to ADP and/or ATP. AMP is also a component in the synthesis of RNA.[3] AMP is present in all known forms of life.[4]
Production and degradation[edit]
AMP does not have the high energy phosphoanhydride bond associated with ADP and ATP. AMP can be produced from ADP:
- 2 ADP → ATP + AMP
Or AMP may be produced by the hydrolysis of one high energy phosphate bond of ADP:
- ADP + H2O → AMP + Pi
AMP can also be formed by hydrolysis of ATP into AMP and pyrophosphate:
- ATP + H2O → AMP + PPi
When RNA is broken down by living systems, nucleoside monophosphates, including adenosine monophosphate, are formed.
AMP can be regenerated to ATP as follows:
- AMP + ATP → 2 ADP (adenylate kinase in the opposite direction)
- ADP + Pi → ATP (this step is most often performed in aerobes by the ATP synthase during oxidative phosphorylation)
AMP can be converted into IMP by the enzyme myoadenylate deaminase, freeing an ammonia group.
In a catabolic pathway, adenosine monophosphate can be converted to uric acid, which is excreted from the body in mammals.[5]
AMP binds to the γ-subunit of AMPK, leading to the activation of the kinase, and then eventually a cascade of other processes such as the activation of catabolic pathways and inhibition of anabolic pathways to regenerate ATP. Catabolic mechanisms, which generate ATP through the release of energy from breaking down molecules, are activated by the AMPK enzyme while anabolic mechanisms, which utilize energy from ATP to form products, are inhibited.[10] Though the γ-subunit can bind AMP/ADP/ATP, only the binding of AMP/ADP results in a conformational shift of the enzyme protein. This variance in AMP/ADP versus ATP binding leads to a shift in the dephosphorylation state for the enzyme.[11] The dephosphorylation of AMPK through various protein phosphatases completely inactivates catalytic function. AMP/ADP protects AMPK from being inactivated by binding to the γ-subunit and maintaining the dephosphorylation state.[12]
https://en.wikipedia.org/wiki/Adenosine_monophosphate
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