Thymidine

Thymidine (deoxythymidine; other names deoxyribosylthymine, thymine deoxyriboside) is a pyrimidine deoxynucleoside. Deoxythymidine is the DNA nucleoside T, which pairs with deoxyadenosine (A) in double-stranded DNA. In cell biology it is used to synchronize the cells in G1/early S phase.

Before the boom in thymidine use caused by the need for thymidine for the production of the antiretroviral drug azidothymidine (AZT), much of the world's thymidine production came from herring sperm. Thymidine occurs almost exclusively in DNA but also occurs in the T-loop of tRNA.

Structure and properties

In its composition, deoxythymidine is a nucleoside composed of deoxyribose (a pentose sugar) joined to the pyrimidine base thymine.

Deoxythymidine can be phosphorylated with one, two or three phosphoric acid groups, creating respectively dTMP, dTDP or dTTP (deoxythymidine mono- di- or triphosphate).

It exists in solid form as small white crystals or white crystalline powder, has a molecular weight of 242.229 u, and has a melting point of 185 °C. The stability of deoxythymidine under standard temperature and pressure (STP) is very high.