Viral Thymidine Kinase
Also written as TK.
Viral-specific activation: Acyclovir is a prodrug that requires phosphorylation by viral thymidine kinase (TK) to become active. α-herpesviruses (HSV-1, HSV-2, VZV) encode their own TK enzyme, while uninfected cells rely on cellular TK with much lower affinity for acyclovir.
What our notes say
- Viral-specific activation: Acyclovir is a prodrug that requires phosphorylation by viral thymidine kinase (TK) to become active. α-herpesviruses (HSV-1, HSV-2, VZV) encode their own TK enzyme, while uninfected cells rely on cellular TK with much lower affinity for acyclovir. (Molecular Biology Exam Review MCQs)
- Viral Thymidine Kinase Activation:Acyclovir is a nucleoside analogue. (Molecular Biology,Molecular Genetics & Microbial-Biochemistry LAQs & SAQs)
- Phosphorylated by viral thymidine kinase (selective for infected cells) (Pharmacology Cheat Code)
- Acyclovir, valacyclovir, famciclovir – guanosine analogs, require viral thymidine kinase for activation (selective toxicity — only works in infected cells) → inhibit viral DNA polymerase (Pharmacology CRASH Course)
- Acyclovir requires viral thymidine kinase for first phosphorylation (EXAM: Vaccines & Antivirals, Rabies, CMV & EBV, Adenovirus & Enteroviruses)
- In HSV-infected cells only, viral thymidine kinase (TK) phosphorylates acyclovir → acyclovir monophosphate (EXAM NOTES: VIROLOGY YR3)