Acrosin of mouse spermatozoa

Area of Science:

• Reproductive biology
• Biochemistry

Background:

• Mouse spermatozoa contain a neutral proteinase, acrosin, primarily in its inactive zymogen form (proacrosin).
• Acrosin plays a critical role in the fertilization process.

Purpose of the Study:

• To characterize mouse acrosin and its role in fertilization.
• To investigate the properties and inhibition of mouse acrosin.

Main Methods:

• Acid and detergent extraction methods were used to isolate acrosin.
• Synthetic inhibitors were employed to study acrosin's active site and substrate specificity.
• Inhibitor studies assessed the relationship between acrosin inhibition and antifertility activity.

Main Results:

• Acid extraction yielded more acrosin than detergent extraction.
• Mouse acrosin has a serine and histidine active site, hydrolyzing lysine and arginine peptide bonds.
• A native sperm-associated inhibitor blocks at least 60% of acrosin activity.
• Acrosin inhibition by natural and synthetic agents prevents gamete union.
• In vitro capacitation did not alter the proacrosin to acrosin ratio.

Conclusions:

• Acrosin activity is essential for successful mouse fertilization.
• The effectiveness of synthetic inhibitors against acrosin correlates with their antifertility effects.
• Understanding acrosin's function and inhibition is key to reproductive science.