    thymidine kinase 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, tk1 and tk2. certain viruses also have genetic information for expression of viral thymidine kinases. thymidine kinase catalyses the reaction: * thd + atp â tmp + adp where thd is deoxythymidine, atp is adenosine 5â-triphosphate, tmp is deoxythymidine 5â-phosphate and adp is adenosine 5â-diphosphate. thymidine kinases have a key function in the synthes
EC_2.7.1 Genes_on_chromosome_16 Genes_on_chromosome_17