Acrosome is formed from the head of the sperm. It contains hydrolytic enzymes which are used to contact and penetrate the egg at the time of fertilization. After ovulation the sperms undergo acrosorfial reaction and release various enzymes (chemicals) contained in acrosome. The enzymes are collectively called sperm lysins containing: [a] Hyaluronidase: Acts on the ground substance of follicle cells. [b] Corona penetrating enzyme: Dissolve corona radiata. [c] Zona lysine or acrosin: It helps to digest the zona pellucida.