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

a virally encoded enzyme that triggers the antiviral therapy to suppress the HSV infection

an enzyme that catalyzes the transfer of phosphate groups and is necessary for the transformation and metabolism of nucleoside analog drugs.