cytidylate

Cytidylic acid, also called cytidylate, is the monophosphate derivative of the nucleoside cytidine, meaning it is cytidine 5'-monophosphate (CMP). It consists of cytosine bound to a ribose sugar, with a single phosphate group attached at the 5' position.

CMP is a fundamental component of RNA chemistry and a key intermediate in nucleotide metabolism. In cells, CMP is formed by phosphorylation of cytidine, typically through cytidine kinase, using ATP as the phosphate donor. CMP can be further phosphorylated to CDP and then to CTP by specific kinases, and it can be dephosphorylated back to cytidine by phosphatases. This interconversion links the cellular energy supply to the nucleotide pool used for RNA synthesis and other pathways.

As a nucleotide, CMP is incorporated into RNA by RNA polymerases as one of the four essential nucleotides. Beyond its role in RNA, CMP and its phosphorylated derivatives serve as activated intermediates in the biosynthesis of other biomolecules; for example, CDP-choline is derived from CTP and is important in phospholipid (cell membrane) synthesis. Thus cytidylic acid sits at a crossroads of genetic information flow and membrane lipid metabolism through its relationships with CDP-activated compounds.

See also: cytidine, cytidine monophosphate (CMP), CDP, CTP, RNA synthesis, phospholipid biosynthesis.