TABLE 1

Effect of neuraminidase mutation on IC₅₀ and enzyme kinetics

Virus	Mean ± SD (fold difference)^a
	IC₅₀ (nM) for:				K_m (μM)
	Zanamivir	Oseltamivir	Laninamivir	Peramivir	K_m (μM)
WT-H273	2.2 ± 1.3	36.1 ± 5.4	2.6 ± 2.0	1.0 ± 0.05	11.5 ± 1.5
Mut-Y273	1.4 ± 0.5 (1)	96.7 ± 10.8 (3)	1.63 ± 0.4 (1)	80.9 ± 6.8 (85)^b	12.3 ± 0.8 (1)
WT-D197	1.6 ± 0.2	35.1 ± 3.3	2.8 ± 1.3	1.0 ± 0.1	13.8 ± 1.3
Mut-N197	4.5 ± 0.7 (3)	66.2 ± 7.5 (2)	5.0 ± 1.2 (2)	3.0 ± 0.7 (3)	30.3 ± 3.3 (3)

↵a Fold difference is from corresponding wild-type values. The data are from three independent experiments.
↵b MUT-Y273 has a significantly higher IC₅₀ for peramivir than that of WT-H273 (Mann-Whitney's U test, P < 0.05).