Herpesvirus thymidine kinase (TK) enzyme catalyzes the phosphorylation of thymidineand thus provides a sufficient pool of thymidine triphosphate for virus DNA synthesis/replication in non-dividing host cells. However, thymidine kinase is non-essential for DNA synthesis/replication
(tk) An enzyme that allows a cell to utilize an alternate metabolic pathway for incorporating thymidine into DNA. Used as a selectable marker to identify transfected eukaryotic cells.
Thymidine kinase TK, is an enzyme, a phosphotransferase (a kinase): 2'-deoxythymidine kinase, ATP-thymidine 5'-phosphotransferase, . It can be found in most living cells. It is present in two forms in mammalian cells, TKI and TKII.