Thymidine Kinase 1 Proteins and Enzymes

Thymidine kinase (TK) belongs to a group of enzymes such as dihydrofolate reductase, thymidylate synthase, and DNA polymerase that are involved in DNA synthesis and precursor production. Two forms have been identified in animal cells, one in cytosol and one in mitochondria. Activity of the cytosolic enzyme is high in proliferating cells and peaks during the S-phase of the cell cycle; it is very low in resting cells due to multiple regulatory mechanisms that ensure expression of these enzymes ...