The inhibition of boar acrosin amidase activity by sulfated polysaccharides

Carbohydrate-protein interactions are known to be important in gamete interactions. We therefore investigated the inhibition of boar sperm acrosin amidase activity by carbohydrates. The sulfated polysaccharides fucoidan and dextran sulfate inhibited amide hydrolysis whereas dextran and various monosaccharides did not inhibit acrosin amidase activity. The kinetics of the inhibition corresponded to those characteristic when multiple forms of an enzyme are present. Such a kinetic result was consistent with the presence of the known autolytically produced forms of acrosin. It was previously shown that sulfated polysaccharides inhibit sperm-egg binding and that acrosin binds carbohydrate. We propose that the sulfated polysaccharide inhibition of acrosin amidase activity observed here is causally related to the previously observed sulfated polysaccharide inhibition of sperm binding to the zona pellucida.