Figure 12

Concentration-dependent inhibition of the enzymatic activities of the 26S proteasome by the CLE or MG-132 in MCF-7 cell extracts. Cell extracts (=50 μg protein) were incubated with 50 μM of the fluorogenic substrates specific for Ch-L, T-L and Cp-L activities in the presence of various concentrations of the CLE for 2 h at 37°C. Each activity was expressed as the percentage of the control (defined as 100%). Panel A &B depicts Ch-L and T-L activities respectively, whereas panel C depicts Ch-L activity with MG-132.