Fig. 4.

Efficacy of specific fluoromethylketone inhibitors at abolishing caspase-specific activity. Caspase-specific activity in H. volcanii cell extracts was measured for IETD-AMC (open bars), LEVD-AMC (black bars), and VEID-AMC (grey bars) in the presence of IETD-fmk, LEVD-fmk and VEID-fmk respectively, at three different concentrations (0, 20, and 50 μM; Enzo Life Sciences). The percent inhibition at each respective concentration (relative to the untreated control) is indicated. For comparison, recombinant human caspase-8 was completely inhibited (> 99%) at 20 μM with both zVAD-fmk and IETD-fmk. Error bars represent standard deviations for triplicate measurements.