Differences in the Properties of Thymidine Kinase Produced in Cells Infected with Type 1 and Type 2 Herpes Virus

Abstract

Thymidine kinase activity is known to increase in BHK 21 cells infected with herpes simplex virus type 1 (Klemperer et al. 1967). Moreover, there is now evidence showing that this is a virus-specified enzyme (Klemperer et al. 1967; Buchan & Watson 1969; Buchan et al. 1970). We now report a similar increase in thymidine kinase activity in BHK 21 cells infected with herpes simplex virus type 2. The pH optima are the same for both enzymes. The growth kinetics are similar and the type 2 virus always induces at least as much enzyme activity as the type 1 and usually up to twice as much. There are striking differences in the stability and serological specificity of the two enzymes. Infected BHK cell extracts were prepared and the thymidine kinase activity measured by the method of Klemperer et al. (1967). Briefly, BHK cells were infected with herpes simplex virus at a multiplicity of infection of 10 to 20 p.f.u./cell.