Involved in the breakdown of propeptides of storage proteins in protein-storage vacuoles (By similarity). Possesses aspartic protease activity in vitro. Optimum pH is 5.0-6.0 with insulin B chain as substrate and at 37 degrees Celsius. Located in protein storage vacuoles (PSV) of the embryo. Expressed in roots, leaves, stems, petals, carpels, seed pods and dry seeds. By light and during senescence. Belongs to the peptidase A1 family.