monophosphateadenosine

Monophosphateadenosine, commonly known as adenosine monophosphate (AMP), is a nucleotide consisting of the adenine base linked to a ribose sugar with a single phosphate group at the 5' position. In biology, AMP serves as an RNA building block and as a free metabolite involved in energy homeostasis and signaling.

Structure: AMP comprises adenine, β-D-ribose, and a phosphate monoester at the 5' carbon. In nucleic acids, AMP is one of the ribonucleotides polymerized to form RNA.

Biosynthesis and metabolism: AMP is produced de novo from inosine monophosphate (IMP) via adenylosuccinate synthetase and adenylosuccinate lyase, using GTP and aspartate. It can also form via the salvage pathway from adenine by adenine phosphoribosyltransferase (APRT) or by phosphorylation of adenosine through adenosine kinase. AMP interconverts with ADP and ATP via kinases and phosphatases. It can be deaminated to IMP by AMP deaminase; 5'-nucleotidases remove the phosphate to yield adenosine, which is further degraded to inosine and downstream purine metabolites.

Biological roles: The cellular AMP level, relative to ATP, reflects energy status and regulates metabolism through AMP-activated protein kinase (AMPK). AMPK activation promotes ATP-generating pathways and inhibits energy-consuming processes. Adenosine produced from AMP can act on adenosine receptors after dephosphorylation; cyclic AMP (cAMP) is formed from ATP by adenylyl cyclase and is degraded to AMP by phosphodiesterases, linking AMP to second-messenger signaling.

Name notes: Although commonly called adenosine monophosphate, monophosphateadenosine is uncommon. AMP is a fundamental nucleotide in genetics and metabolism, with roles in nucleic acid synthesis, energy balance, and signaling.