Fig. 3.

Activity assays with fluorogenic substrates. Proteasome activities were assayed in cell extracts using fluorogenic substrates for the chymotrypsin-like (s-LLVY-AMC), trypsin-like (Boc-LRR-AMC), caspase-like (Z-LLE-AMC) as well as for the β5i (Ac-ANW-AMC) and β1i-associated (Ac-PAL-AMC) activities. Fluorescence intensity was measured in a fluorimeter and activity was expressed as arbitrary fluorescence units (FU) min⁻¹ µg⁻¹ of total proteins. Bars represent the mean ± SD of the values obtained in at least three extracts deriving from different batches of cells. *p < 0.05; **p < 0.01; ***p < 0.001 vs 23132/87