TABLE 3.

Characterization of NS3 protease variants in HCV enzyme assays^a

Variant	Enzymatic IC50(1 h) of telaprevir (μM)	Fold change
Wild type (genotype 1a; n = 5)	0.050 ± 0.031	1.0 ± 0.6
V36M (n = 4)	0.27 ± 0.11	5.4 ± 2.1
V36L (n = 4)	0.13 ± 0.03	2.6 ± 0.6
V36M + R155K (n = 5)	3.4 ± 1.2	69 ± 24
Wild type (genotype 1b; n = 4)	0.063 ± 0.051	1.0 ± 0.8
V36A (n = 4)	0.23 ± 0.12	3.6 ± 1.9

^aThe average enzymatic IC_{50(1 h)} values ± SDs of telaprevir were determined for the purified genotype 1a or 1b wild-type protease domains and for four variant HCV NS3 serine protease domains by using the KK4A cofactor peptide and the fluorescent resonance energy transfer substrate in three to five independent experiments. The fold change was determined by dividing the enzymatic IC_{50(1 h)} of a given variant by that of the corresponding wild-type protease (genotype 1a or 1b).