cytidylyl

Cytidylyl is a chemical group derived from cytidine monophosphate (CMP) and is used in biochemistry to denote the cytidine monophosphate moiety when it is transferred or linked to another molecule. In systematic and enzyme nomenclature, cytidylyl serves as the naming stem for enzymes that transfer cytidylyl groups, such as cytidylyltransferases, which catalyze the transfer of the cytidylyl moiety from CTP to an acceptor substrate.

In biological contexts, cytidylyl-containing intermediates are important in the synthesis of several key biomolecules. For example, CDP-choline is formed by cytidylyltransferase activity in the CDP-choline pathway, and CDP-diacylglycerol is produced by CDP-diacylglycerol synthase, a cytidylyltransferase reaction. These CDP-activated intermediates serve as activated donors in the formation of phospholipids and other essential lipids, as well as in certain nucleic acid–related processes.

Because cytidylyl is a moiety rather than a standalone molecule, it appears primarily in the context of enzymatic reactions and in the names of enzymes that manipulate cytidylyl-containing substrates. The term has related forms, including cytidylate and cytidine, which refer to the nucleotide pool itself or to related derivatives.

See also cytidylyltransferase, CDP-diacylglycerol, CDP-choline, cytidylyl phosphate, cytidylyl group, cytidine, cytidylate.