Caspase activity in a cell-free system.

Cytosols were isolated using an STE buffer as described in “Materials and methods.” Cytosols were then incubated at 30°C for 1 hour in the absence or presence of 1 mM dATP or 1 mM CdATP and in the absence or presence of 40 nM cytochrome c. Extracts were then plated onto a 96-well plate, and caspase-3–like activity was quantitated with the DEVD-AMC reagent on a spectofluorometer as described previously. Results are characteristic of 3 independent experiments.