Thymidylate kinase (EC 2.7.4.9; dTMP kinase) catalyzes the phosphorylation of thymidine 5'-monophosphate (dTMP) to form thymidine 5'-diphosphate (dTDP) in the presence of ATP and magnesium:

ATP + thymidine 5'-phosphate ${\displaystyle \rightleftharpoons }$ ADP + thymidine 5'-diphosphate

Thymidylate kinase is a ubiquitous enzyme of about 25 Kd and is important in the dTTP synthesis pathway for DNA synthesis. The function of dTMP kinase in eukaryotes comes from the study of a cell cycle mutant, cdc8, in Saccharomyces cerevisiae. Structural and functional analyses suggest that the cDNA codes for authentic human dTMP kinase. The mRNA levels and enzyme activities corresponded to cell cycle progression and cell growth stages.^[1]

Thymidylate kinase's subfamily is predicted thymidylate kinase, TKRP1. InterPro: IPR014505

Human protein DTYMK contains this domain.

As of late 2007, 40 structures have been solved for this class of enzymes, with PDB accession codes 1E2D, 1E2E, 1E2F, 1E2G, 1E2Q, 1E98, 1E99, 1E9A, 1E9B, 1E9C, 1E9D, 1E9E, 1E9F, 1G3U, 1GSI, 1GTV, 1MRN, 1MRS, 1N5I, 1N5J, 1N5K, 1N5L, 1NMX, 1NMY, 1NMZ, 1NN0, 1NN1, 1NN3, 1NN5, 1TMK, 1W2G, 1W2H, 2CCG, 2CCJ, 2CCK, 2PBR, 2TMK, 3TMK, 4TMK, and 5TMP.

• Thymidine kinase
• Thymidylate synthase
• Thymidine kinase in clinical chemistry