The acrosome reaction must be completed before the sperm can fuse with the secondary oocyte, during the process of fertilisation. It occurs when the sperm comes into contact with the corona radiata of the secondary oocyte. Initally, perforations will develop in the acrosome, and then there will be point fusions of the sperm plasma membrane and the outer acrosomal membrane.

The acrosome reaction is associated with the release of enzymes which facilitate fertilisation. The passage of sperm through the corona radiata is dependent on hyaluronidase, an acrosomal membrane, as well as tubal mucosal enzymes. Flagella action of the sperm also helps penetration of the corona radiata. Other important acrosomal enzymes include esterases, and lysin which causes lysis of the zona pellucida.

In Eutherian mammals the acrosome contains digestive enzymes (including hyaluronidase and acrosin).

The acrosome contains digestive enzymes that are used to break down the outer membrane of the ovum.

If a sperm has a defective acrosome reaction, that sperm will not be able to penetrate the outer shell of the egg. Fertilization would not occur.

The acrosome is derived from the Golgi apparatus and contains hydrolytic enzymes.
it comes from the testes