Figure 2.
Properties of caspase variants. (A) Anti-caspase-3 immunoblot of procaspase-3(D3A), procaspase-3(D3N), procaspase-3(D3E), procaspase-3(D169A), procaspase-3(D3A/E167A), mature caspase-3, procaspase-3(D3A/Y203F), or procaspase-3(D3A/E173A). The dashed line signifies the use of two gels. (B) Procaspase-3(D169A) incubated with mature caspase-3. Bands 1–7 represent cleavage products as described in the text. O/N refers to overnight incubation (>16 h). (C) In the top panel, procaspase-3(D3A/E173A) was incubated with serine protease inhibitors for 4 days. In the bottom panel, procaspase-3(D3A/E173A) was incubated with the irreversible inhibitor Ac-DAVD-CMK for 4 days. Aliquots were removed each 24 h, and the samples were examined as described in Experimental Procedures. FL refers to full-length protein (32 kDa), and M refers to molecular mass markers.