title: Effects of a membrane-bound trypsin-like proteinase and seminal proteinase inhibitors on the bicarbonate-sensitive adenylate cyclase in porcine sperm plasma membranes.
abstract: Plasma membranes were purified from flagella of porcine cauda epididymal sperm and proteolytic regulation of bicarbonate-sensitive adenylate cyclase was studied. It was found that the epididymal sperm plasma membrane contained a trypsin-like proteinase which inactivated adenylate cyclase. Bicarbonate activates adenylate cyclase as reported previously, but, at the same time, the anions enhance the inactivation of the enzyme by the membrane-bound trypsin-like proteinase. This phenomenon is not due to the direct activation of the proteinase, but closely related to the activation of adenylate cyclase by bicarbonate. It was also found that seminal proteinase inhibitors blocked the inactivation of adenylate cyclase and maintained the bicarbonate activation of the enzyme at high level. Actually, bicarbonate keeps adenylate cyclase fully active in ejaculated sperm, because membrane-bound proteinase is completely inhibited by the seminal proteinase inhibitors. These results suggest that the interactions between membrane-bound proteinase and seminal proteinase inhibitor are involved in the regulation of the bicarbonate-sensitive adenylate cyclase system.
authors.affiliation: Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Okamura
authors.forename: S
authors.initials: S
authors.lastname: Onoe
authors.forename: K
authors.initials: K
authors.lastname: Kawakura
authors.forename: Y
authors.initials: Y
authors.lastname: Tajima
authors.forename: Y
authors.initials: Y
authors.lastname: Sugita
mesh_terms: D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D010450:Endopeptidases / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D004822:Epididymis / Q000187:drug effects / Q000201:enzymology; D006868:Hydrolysis; D007700:Kinetics; D008297:Male; D011480:Protease Inhibitors / Q000494:pharmacology*; D012964:Sodium / Q000494:pharmacology*; D017693:Sodium Bicarbonate; D013094:Spermatozoa / Q000187:drug effects / Q000201:enzymology*; D013552:Swine
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D001639:Bicarbonates; D011480:Protease Inhibitors; D017693:Sodium Bicarbonate; D012964:Sodium; D010450:Endopeptidases