. 2009 Jul 21;284(39):26439–26446. doi: 10.1074/jbc.M109.012500

TABLE 4.

Kinetic constants for dGTP and ACV-TP incorporation

Values were calculated by fitting the data points to Michaelis-Menten function using GraphPad Prism (version 5.0).

Enzyme	dGTP			ACV-TP			SEL^c
Enzyme	V_max^a	K_m^b	V_max/K_m	V_max	K_m	V_max/K_m	SEL^c
	nm/min	μm		nm/min	μm
UL54^d	2.2 ± 0.086^e	0.041 ± 0.0067	54	1.2 ± 0.13	0.039 ± 0.023	31	1.7
gp43^f	9.2 ± 0.12	0.079 ± 0.0053	117	8.6 ± 0.45	24 ± 2.8	0.36	325
ABC	5.1 ± 0.23	0.47 ± 0.10	11	5.1 ± 0.14	0.41 ± 0.059	12.4	0.87

^a V_max is the maximum velocity of the reaction.

^b K_m is the substrate concentration at half-maximum velocity of the reaction.

^c SEL means selectivity, which is calculated as a ratio of k_pol/K_d for dGTP over k_pol/K_d for ACV-TP.

^d UL54, the HCMV polymerase, was expressed in the in vitro transcription/translation system. The previously reported UL54 value for dGTP K_m is 0.11 μm (42).

^e Standard deviations were determined on the basis of at least two independent experiments.

^f The previously reported gp43 value for dGTP K_m is 0.17 μm (51).