TABLE 4.

RNA-stimulated NTPase activities of WT and Q221L mutant NS3-NS4A^a

NS3-NS4A protein	Km (nM)	Vmaxb	kcatc	Catalytic efficiencyd	RNA stimulation factor
WT	2.0 ± 1.0	0.29 ± 0.03	0.16 ± 0.03	80	2.2
Q221L	200 ± 60	0.26 ± 0.01	0.15 ± 0.01	0.8	2.4

^aThe data shown are averages ± standard deviations or averages from three experiments.

^bValues were calculated before normalization and are expressed as nanomoles of ATP hydrolyzed per minute.

^cValues are expressed as nanomoles of ATP per minute per picomole of NS3-NS4A.

^dValues were calculated as k_cat/K_m and are expressed as nanomoles of ATP hydrolyzed per minute per picomole of protein per μM of RNA.