Preliminary characterization of multiple hyaluronidase forms in boar reproductive tract

Hyaluronidases play an important role in gamete interaction and fertility in mammals. The objectives of the present study were to investigate multiple forms of the enzyme in boar reproductive tract using electrophoretic methods. Two forms of hyaluronidase (EC 3.2.1.35) were detected in boar seminal plasma (relative molecular masses of 55,000 and 65,000) using hyaluronic acid-substrate polyacrylamide gel electrophoresis in the presence of SDS. These two forms can be separated by means of affinity chromatography on Heparin-Sepharose. They differ, besides their affinity to heparin, also in the pH optimum of their enzymatic activity. The form with relative molecular mass of 55,000 was active both at the acidic (pH 3.7) and the neutral pH (pH 7.4) and was bound to immobilized heparin. The second form (relative molecular mass 65,000) was active only at acidic pH and did not interact with heparin. The same acidic-active form (65,000) was found in seminal vesicle fluids. The hyaluronidase form which is active both at the acidic and the neutral pH (51,000) was detected in epididymal fluid. In the detergent extracts of boar sperm, three active forms of the enzyme were found (relative molecular masses 55,000, 70,000 and 80,000). The form of relative molecular mass 55,000 was active in a wide range of pH (pH 3-8). The forms of relative molecular masses 70,000 and 80,000 were active only at neutral pH.