Zona pellucida

The zona pellucida is a glycoprotein matrix surrounding the plasma membrane of a mammalian oocyte. This structure binds spermatozoa, and is required to initiate the acrosome reaction. The zona glycoprotein, ZP3 , is responsible for sperm binding, adhering to proteins on the sperm plasma membrane. There is evidence that ZP3 is then involved in the induction of the acrosome reaction, whereby a spermatozoon releases the contents of the acrosomal vesicle.

Reference

• Oehninger S. 2003. Biochemical and functional characterization of the human zona pellucida. Reprod Biomed Online 7:641-8.