title: Acrosin inhibition. Comparisons of membrane-associated and -solubilized enzyme.
abstract: Acrosin is an extrinsic membrane proteinase from spermatozoa which functions in the fertilization process. Liposomes were utilized as a model system to determined possible effects of membrane association on acrosin's enzymatic activity. By comparison with solubilized enzyme, liposome-bound acrosin had a substantial reduction in the apparent affinity for "progressive" inhibitors such as leupeptin, lima bean trypsin inhibitor, soy bean trypsin inhibitor, and for a proteinase inhibitor from sperm extracts. In contrast, the liposome-bound and -solubilized enzymes were essentially identical with respect to the binding of benzamidine and p-aminobenzamidine which are competitive acrosin inhibitors. These results suggest membrane association can influence some but not all of acrosin's enzymatic properties.
mesh_terms: D000176:Acrosin / Q000037:antagonists & inhibitors*; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D007700:Kinetics; D008081:Liposomes; D008297:Male; D011480:Protease Inhibitors; D012995:Solubility; D013094:Spermatozoa / Q000201:enzymology*; D013552:Swine
chemical_list: D008081:Liposomes; D011480:Protease Inhibitors; D000176:Acrosin