Involved in the activation cascade of caspases responsible for apoptosis execution (PubMed:8521391, PubMed:8576161, PubMed:8567622, PubMed:9070923, PubMed:11701129). Cleaves and activates sterol regulatory element binding proteins (SREBPs) (PubMed:8521391, PubMed:8576161, PubMed:8567622, PubMed:9070923). Proteolytically cleaves poly(ADP-ribose) polymerase (PARP) at a '216-Asp-|-Gly-217' bond. Overexpression promotes programmed cell death (PubMed:8521391, PubMed:8576161, PubMed:8567622, PubMed:9070923). Cleaves phospholipid scramblase proteins XKR4, XKR8 and XKR9 (By similarity). Lacks enzymatic activity. Strict requirement for an Asp residue at position P1 and has a preferred cleavage sequence of Asp-Glu-Val-Asp-|-. Inhibited by isatin sulfonamides. Heterotetramer that consists of two anti-parallel arranged heterodimers, each one formed by a 20 kDa (p20) and a 11 kDa (p11) subunit. Interacts with BIRC6/bruce. Interacts with ATXN3 (short isoform 1) (PubMed:30455355). Interacts with HSPA5 (PubMed:26045166). Highly expressed in lung, skeletal muscle, liver, kidney, spleen and heart, and moderately in testis. No expression in the brain. Cleavages by granzyme B or caspase-10 generate the two active subunits. Propeptide domains can also be cleaved efficiently by caspase-3. Active heterodimers between the small subunit of caspase-7 and the large subunit of caspase-3, and vice versa, also occur. What we call isoform Alpha' is also known as Beta. Belongs to the peptidase C14A family.