title: Demonstration of a new acrosin inhibitor in human seminal plasma.
abstract: We have recently described the purification and characterization of a tumor-associated trypsin inhibitor (TATI). Studies on its N-terminal sequence suggested identity with the pancreatic secretory trypsin inhibitor (PSTI) (Huhtala, M.-L., Pesonen, K., Kalkkinen, N. & Stenman, U.-H. (1982) J. Biol. Chem. 257, 13713-13716). I report here the occurrence of a TATI-like activity in human seminal plasma. Concentrations of this inhibitor in seminal plasma varied considerably (4-500 ng/ml, n = 50). In radioimmunoassay the dose-response curves of the new seminal plasma inhibitor and purified TATI were parallel. The similarity between these two inhibitors was demonstrated by gel filtration, reverse phase liquid chromatography and ion-exchange chromatography. By ion exchange chromatography the new inhibitor could be separated from the main seminal plasma trypsin inhibitors. Purified TATI was shown to inhibit human acrosin effectively.
mesh_terms: D000176:Acrosin / Q000037:antagonists & inhibitors*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D010051:Ovarian Neoplasms / Q000378:metabolism; D010447:Peptide Hydrolases / Q000032:analysis; D029584:Prostatic Secretory Proteins; D011480:Protease Inhibitors; D011506:Proteins / Q000494:pharmacology*; D011863:Radioimmunoassay; D012661:Semen / Q000378:metabolism*; D029589:Seminal Plasma Proteins; D013094:Spermatozoa / Q000032:analysis / Q000201:enzymology; D014357:Trypsin / Q000032:analysis; D014361:Trypsin Inhibitors / Q000378:metabolism
chemical_list: D029584:Prostatic Secretory Proteins; D011480:Protease Inhibitors; D011506:Proteins; D029589:Seminal Plasma Proteins; D014361:Trypsin Inhibitors; C043076:beta-microseminoprotein; D010447:Peptide Hydrolases; D000176:Acrosin; D014357:Trypsin