Figure 1

(A) Normalized concentration−response plot for Copper(II)-mediated inhibition of ChT-L, T-L and C-L residual activities of hCP (upper panel). The lower panel report the peptidase activities as a semilog plot fitted by Equation 1. IC₅₀ values for the distinct peptidase activities and the related fitting parameters are reported in Table 1. (B) Native gel electrophoresis of free 20S proteasome (0.2 μg). hCP was exposed to increasing amounts of Cu(II) ions for 60 min and silver stained as described in the experimental section.