Involved in the breakdown of propeptides of storage proteins in protein-storage vacuoles. Prefers hydrophobic residues Phe, Val, Ile, Leu, and Ala at P1 and P1', but also cleaves -Phe-|-Asp- and -Asp-|-Asp- bonds in 2S albumin from plant seeds. Heterodimer of two subunits (29 kDa and 11 kDa) processed from the precursor molecule. A large enzyme (32 kDa and 16 kDa) is an intermediate precursor form. Embryo and leaf. Belongs to the peptidase A1 family.