Fig. 4. Mutating amino acid D9 to A9 decreases the apoptotic activity of caspase-3.

a Point mutations within the prodomain and the interdomain linker were created and indicated in red. Caspase-3 protein expression was determined by western blot analysis. Actin was used as a loading control. b A caspase-3 activity assay was used on the indicated cell lines to determine the ability to cleave a DEVD-chromphore substrate. c The caspase-3 point mutation cells were subjected to cell death analysis via Annexin V/PI staining using flow cytometry. Data are presented as mean ± SEM of at least three independent experiments. *p > 0.05, **p > 0.01, ***p > 0.001