Deoxycytidine

Deoxycytidine is a nucleoside composed of cytosine attached to a 2'-deoxyribose sugar via a beta-N-glycosidic bond. It is one of the four canonical deoxyribonucleosides found in DNA, the others being deoxyadenosine (dA), deoxyguanosine (dG), and deoxythymidine (dT).

In cells, deoxycytidine serves as a precursor in the generation of deoxynucleotide pools used for DNA synthesis and repair. It is formed through de novo nucleotide synthesis and salvage pathways. The nucleoside can be phosphorylated by the enzyme deoxycytidine kinase to form deoxycytidine monophosphate (dCMP); subsequent phosphorylation yields dCDP and dCTP, the active dNTPs for DNA replication.

Structurally, the cytosine base pairs with guanine in DNA via three hydrogen bonds, and the deoxyribose sugar lacks a 2'-OH group, distinguishing deoxyribonucleosides from ribonucleosides. In DNA synthesis, dCTP is the direct substrate for incorporation into the growing DNA strand by DNA polymerases.

In laboratory and biotechnological contexts, deoxycytidine and its phosphorylated derivatives are used in nucleotide synthesis, DNA sequencing, and oligonucleotide synthesis workflows. Related cytidine analogs and nucleotides are common tools in research and medicine; for example, deoxynucleoside triphosphates are substrates for polymerases, while clinically used cytosine analogs include various chemotherapeutic agents.