Multiple forms of human acrosin: isolation and properties

Area of Science:

• Biochemistry
• Reproductive Biology
• Enzymology

Background:

• Human acrosin is a key enzyme in sperm function.
• Understanding its molecular forms is crucial for reproductive research.

Purpose of the Study:

• To purify and characterize human acrosin.
• To investigate the different molecular forms of human acrosin.
• To explore the relationship between acrosin forms and enzyme activation.

Main Methods:

• Acidic extraction of ejaculated spermatozoa.
• Gel filtration chromatography (Sephadex G-75).
• Affinity chromatography (p-amino-benzamidine Sepharose).
• Glycoprotein binding assays (Concanavalin A-Sepharose).

Main Results:

• Human acrosin was purified into electrophoretically homogeneous forms.
• At least four molecular forms of human acrosin were identified.
• Molecular weights of three forms were determined as 64,000, 38,000, and 25,000 Da.
• A high molecular weight form converts to lower molecular weight forms near neutral pH.
• Human acrosin is a glycoprotein, binding reversibly to Concanavalin A-Sepharose.
• The 25,000 Da form shares amino acid similarity with human trypsin.
• Antibodies against boar acrosin cross-react with human acrosin.

Conclusions:

• Human acrosin exists in multiple molecular forms with distinct molecular weights.
• Interconversion of acrosin forms suggests a process of proenzyme activation.
• These findings contribute to understanding acrosin's role in fertilization and potential therapeutic targets.