Oocyte-specific oolemmal receptor involved in sperm and egg adhesion and fertilization. Plays a role in the polyspermy inhibition. Probably acts as a protease for the post-fertilization cleavage of ZP2. Cleaves the sperm-binding ZP2 at the surface of the zona pellucida after fertilization and cortical granule exocytosis, rendering the zona pellucida unable to support further sperm binding. Binds 1 zinc ion per subunit. Interacts (via N-terminal domain) with SPACA3; the interaction occurs during fertilization. Probably exocytosed from cortical granules during post-fertilization. Detected throughout the ooplasm of germinal vesicle stage oocytes in early bilaminar secondary follicles at postnatal (PN) day 3. Detected in the microvillar domain of the oolemma in arrested ovulated secondary oocytes and in the first polar body prior to fertilization. Upon fertilization, detected in the perivitelline space (PVS) and occasionally on the oolemma in 2-cell through morulae stages. Colocalizes with SPACA3 at the microvillar domain of the oolemma and in the perivitelline space (PVS). Life's boundaries - Issue 141 of September2012