TABLE 2.

Inhibition of HSV DNA polymerases by A-5021 triphosphate^a

Polymerase	Km (μM)b dGTP	Ki (μM) for indicated triphosphatec:
		A-5021	ACV	(R,S)PCVd
HSV-1 (KOS)	0.24 ± 0.01	0.020 ± 0.002	0.0051 ± 0.0012	3.7 ± 0.1
HSV-2 (UW-268)	0.18 ± 0.01	0.017 ± 0.003	0.0067 ± 0.0007	3.0 ± 0.2

^aActivated calf thymus DNA was used as the template primer. Values are the means ± standard errors of three determinations. 

^bK_m from Lineweaver-Burk plots. 

^cK_i from secondary plots of Lineweaver-Burk plots. 

^dAll triphosphates of nucleoside analogs were chemically synthesized. (R,S)-PCV triphosphate was the racemic form, while the biosynthesized form in HSV-1-infected cells was almost entirely the (S)-enantiomer (>95%). In HSV-2-infected cells, 90% of the triphosphate was (S)- and 10% was the (R)-enantiomer (26).