Practice question

Permanent elimination of sperm binding capacity during slow block involves enzymatic destruction of specific recognition molecules. Cortical granules discharge large trypsin-like serine protease that cleaves peptide linkages anchoring EBR1 bindin receptor complex to vitelline envelope glycoprotein scaffold and degrades residual fertilizing sperm proteins adhering to envelope. This proteolytic destruction ensures no new bindin-receptor interactions can reform even before envelope hardening physically completes. Acrosomal protease facilitates sperm entry through jelly, ovoperoxidase catalyzes dityrosine crosslinks hardening envelope, phospholipase C generates IP3 for calcium release but does not degrade receptors. Thus enzyme responsible for cleaving bindin receptors is cortical granule serine protease.