CMP is a pyrimidine nucleotide that is an intermediate in several metabolic pathways. It arises from synthesis of phosphatidic acid-containing compounds. In addition to being an intermediate in de novo pyrimidine biosynthesis, it participates in the reactions that follow:

1. CTP + Sialic acid <=> CMP-Sialic acid

2. CDP--Choline + Diacylglycerol <=> CMP + Phosphatidylcholine (catalyzed by CDP-Choline: 1,2-Diacylglycerol Phosphocholine Transferase)

3. CMP + H2O <=> Cytidine + Pi (catalyzed by Nucleotidase)