Figure 3. Inhibition of Proteasome induction by cyclohexamide.

Panel A. MEF cells were incubated with 100 μg/ml of cyclohexamide (or not treated) in an attempt to block H₂O₂ induced expression of proteolytic enzymes. Cells were then grown to 50% confluence and exposed (in PBS) to a transient adaptive pre-treatment 2 μmol of H₂0₂ per 10⁷ cells, harvested, and lysed, as described in the legend to Figure. 1. Proteolytic activity assays for degradation of suc-LLVY-AMC were then performed, as per Figs. 1 and 2. Panel B. Inhibition of proteasome induction plotted as the percent inhibition (means ± SE, n = 3) exerted by cycloheximide against the H₂O₂ induced (adaptive) proteasome activity of panel A.