β-D-Glucuronidase is associated with goat sperm cytoskeleton

Glycosidase activities were detected as detergent‐insoluble after sequential extractions of goat sperm with Triton X‐100. Seventy percent of total β‐glucuronidase activity was found in the detergent‐insoluble fraction. This portion of β‐glucuronidase was resistant to extractions in the presence of 1 M KCl, chaotropic agents, colchicine, or cytochalasin B, being only partially solubilized by 3 M KCl or DNAse I treatment. The treatment with 0.1% sodium deoxycholate was effective, releasing 73% of the enzyme activity. Treating the deoxycholate extract with DNAse I resulted in a change in the elution profile of β‐glucuronidase as judged by gel filtration chromatography. A polyclonal antibody was developed against pancreatic β‐glucuronidase, and the sperm enzyme was strongly inhibited by the IgG fraction of this antibody. Western blot analysis showed that the same protein correspond to both Triton‐soluble and insoluble enzyme. Results demonstrate that β‐glucuronidase is tightly bound to the Triton X‐100 resistant fraction, suggesting that the enzyme is associated to sperm cytoskeleton. J. Exp. Zool. 289:146–152, 2001. © 2001 Wiley‐Liss, Inc.