Thymidine Kinase from Herpes Simplex Virus Type 1 (HSV1-TK)

Thymidine kinase from herpes simplex virus type 1 (HSV1-TK) is a viral enzyme encoded by the UL23 gene of HSV-1. It catalyzes the transfer of a phosphate group from ATP to thymidine, producing thymidine monophosphate (dTMP), essential for viral DNA replication. Unlike human TK1, HSV1-TK has broad substrate specificity, including pyrimidines, pyrimidine analogs (AZT), and purine/purine analogs such as acyclovir (ACV) and ganciclovir (GCV). It is used in antiviral therapy, suicide gene therapy for cancer, and as a reporter system.

Other names

HSV-1 Thymidine KinaseUL23 gene productTKHSV_I

Phosphorylation of nucleoside analogs to monophosphate form, leading to inhibition of viral DNA polymerase after further phosphorylation by cellular kinases.