Figure 5.
Dose–response plot for quercetin-3-β-galactoside on the proteolytic activity inhibition of SARS-CoV 3CLpro and SARS-CoV 3CLpro Q189A. Inhibition of cleavage was measured by FRET using a peptide substrate labeled with a pair of fluorogenic dyes. IC50 values were calculated from the curves using nonlinear regression analysis. IC50 value for quercetin-3-β-galactoside on SARS-CoV 3CLpro is 42.79 ± 4.97 μM (A). IC50 value for quercetin-3-β-galactoside on SARS-CoV 3CLpro Q189A is 127.89 ± 10.06 μM (B).