Figure 12.

(A) Influence of the substituent at the meta position of the benzoyl residue at P3 on the inhibition of cathepsin L. The measurement was performed in three independent experiments (each as a duplicate determination) in assay buffer (pH 6.0) containing 10 μM Z-FR-AMC, 25 ng/mL cathepsin L, and 1.5% DMSO. (B) Relationship between the van der Waals radii of the substituents at the meta position of the P3 benzoyl residue and the cathepsin L inactivation constant. The data point for the CF₃ substituent was excluded from calculating the regression line.