Purification of boar acrosomal arylsulfatase A and possible role in the penetration of cumulus cells.

Abstract

Arylsulfatase A was extracted and purified from boar epididymal sperm acrosomes. Acrosomes were extracted by sonication in 50 mM Tris-maleate buffer containing 50 mM MgCl2, pH 6.1, followed by treatment with 50 mM Tris-maleate plus 0.2% Brij-35, pH 6.1. Purification of arylsulfatase A was performed with a three-step procedure consisting of centrifugation (85,000 X g), affinity chromatography with p-aminobenzamidine-Sepharose followed by chromatography on diethyaminoethyl (DEAE) Sephadex. The specific activity of the purified enzyme was 54 mumol/h per mg protein. The purified arylsulfatase did not contain any detectable acrosin or hyaluronidase activities. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis revealed a major band with an estimated molecular weight of 65,000 daltons. Properties of arylsulfatase A, determined by hydrolysis of p-nitrocatechol sulfate, indicated that the enzyme was inhibited 46% by 3.1 microM Ag+ and had a pH optimum of 4.2. Boar acrosomal arylsulfatase A dispersed the cumulus cells of ovulated hamster and rabbit eggs as well as those of follicular pig eggs. No effect of the enzyme on the zona pellucida or the oolemma was observed.