Acrosin

Acrosin is a proteolytic enzyme that plays a crucial role in the fertilization process. It is found in the acrosome, a specialized organelle that covers the anterior part of the spermatozoon's head.

Function

Acrosin is released during the acrosome reaction, a process that occurs when the spermatozoon comes into contact with the zona pellucida of the oocyte. The enzyme then acts on the zona pellucida, facilitating the penetration of the spermatozoon through this protective layer and allowing it to reach the oocyte's plasma membrane.

Structure

Acrosin is a serine protease, meaning it has a serine residue at its active site. It is initially produced as proacrosin, an inactive precursor, and is activated by the action of other enzymes in the acrosome.

Clinical significance

Defects in acrosin production or function can lead to infertility. Some forms of male infertility are associated with low acrosin activity, suggesting that this enzyme is essential for successful fertilization.

See also

• Acrosome reaction
• Zona pellucida
• Spermatozoon
• Oocyte
• Fertilization