Bovine sperm forward motility protein. Partial purification and characterization.

Area of Science:

• Reproductive Biology
• Biochemistry
• Spermatozoa Motility

Background:

• Immature spermatozoa from the caput epididymis lack motility.
• Bovine seminal plasma contains a factor that induces forward motility.

Purpose of the Study:

• To characterize the protein responsible for initiating sperm forward motility.
• To develop an improved assay for studying sperm motility.

Main Methods:

• Fractionation by charge and molecular weight.
• Molecular sieving under dissociating conditions (urea, SDS/DTT).
• Partial purification via heat treatment, gel chromatography, and affinity chromatography.
• Enzymatic treatments (beta-galactosidase, neuraminidase, alpha-mannosidase, galactose oxidase, trypsin).

Main Results:

• The motility-initiating protein exists as aggregates but has a monomeric molecular weight of 37,500.
• Purification yielded a protein partially characterized by heat, gel, and affinity chromatography.
• Enzymatic studies indicated the protein is a glycoprotein, with activity reduced by specific glycosidases and abolished by trypsin.

Conclusions:

• The forward motility protein is a glycoprotein essential for initiating sperm motility.
• This protein likely plays a role in the epididymal development of sperm motility capacity.