TABLE 1.

Steady-state constants of wild-type and S282T NS5B polymerases for RNA templates during initiation^a

NS5B polymerase	Nucleotide	Km (μM)	Vmax (s−1)	Vmax/Km (s−1/μM)	Discrimination (fold)	Resistance (fold)
WT	CTP	13 ± 0.4	12 × 10−3 ± 0.7 × 10−3	9.2 × 10−4
	2′-O-Me-CTP	189 ± 24	4.7 × 10−3 ± 0.1 × 10−3	2.5 × 10−5	36
	2′-C-Me-CTP	20 ± 6	7 × 10−3 ± 0.3 × 10−3	3.5 × 10−4	2.5
S282T mutant	CTP	7 ± 1	2.5 × 10−3 ± 0.07 × 10−3	3.5 × 10−4
	2′-O-Me-CTP	48 ± 10	0.9 × 10−3 ± 0.05 × 10−3	1.6 × 10−5	21	0.7
	2′-C-Me-CTP	ND	ND	0

^aDiscrimination was determined as the ratio (V_max/K_m)_CTP/(V_max/K_m)_analogue. Resistance was determined as the ratio (V_max/K_m)_WT/(V_max/K_m)_mutant. K_m and V_max were calculated as described in Materials and Methods. V_max is expressed in pmol s⁻¹ · pmol⁻¹ enzyme. ND, not detectable.