Table 3

Inhibition of thymidylate synthase by BVDU in intact Ost TKcells transfected with the HSV-1 TK(WT) and HSV-1 TK(Q125N) gene

[5-3H]dUrd Incubation timeOst TK/ HSV-1 TK(WT)+Ost TK/ HSV-1 TK(Q125N)+
1 h>100 μM9.8  ± 5.1 μM
2 h>100 μM3.3  ± 2.2 μM

The ability of BVDU to inhibit thymidylate synthase in Ost TK/HSV-1 TK(WT)+ and Ost TK/HSV-1 TK(Q125N)+ cells was measured by the evaluation of tritium release from [5-3H]dUrd after 1 and 2 h.