Asparagine-specific endopeptidase that may be involved in processing of proteins targeted to vacuoles (By similarity). Probably involved in post-translational proteolysis of seed storage proteins in the protein storage vacuole of developing seeds (PubMed:12417707, PubMed:14688293). Exhibits a caspase-1-like activity in extracellular granules. At the early stage of seed development, required for the formation of the seed coat, by regulating cell death of specific cell layers in inner integument (PubMed:15705955). Hydrolysis of proteins and small molecule substrates at -Asn-|-Xaa- bonds. Strongly inhibited by biotin-YVAD-fmk (a caspase-1 inhibitor) and by Ac-DEVD-fmk. Localized to electron-dense structures inside and outside the walls of seed coat cells that undergo cell death. Seed specific. Restricted to developing seeds at 7 days after anthesis, and, at lower levels, detected in flowers (PubMed:12417707, PubMed:14688293). Detected in siliques, specifically in seed coats (at protein level) (PubMed:15705955). Specifically and transiently expressed in two cell layers of the seed coat (ii2 and ii3) at an early stage of seed development (at protein level). Auto-catalytic activation. No macroscopic phenotype, probably due to functional redundancy (PubMed:12417707, PubMed:14688293). In plants lacking all vacuolar-processing enzyme isozymes (e.g. alpha, beta, gamma and delta) shift of storage protein accumulation from normally processed polypeptides to a finite number of prominent alternatively processed polypeptides cleaved at sites other than the conserved Asn residues targeted by VPE (PubMed:14688293). Delayed cell death of the two layers of the seed coat (PubMed:15705955). Belongs to the peptidase C13 family.