title: Further purification and characterization of acid-stable protease inhibitor from ascites of an ovarian carcinoma patient.
abstract: An acid-stable protease inhibitor (AS-PI) has been previously demonstrated in ascitic fluid from patients with ovarian carcinoma. In this study, the AS-PI was further purified using DEAE-cellulose and isoelectric focusing (IEF), and a partial characterization was undertaken. On DEAE-cellulose ion-exchange column chromatography, AS-PI activity was observed in both adsorbed and non-adsorbed fractions. The former represented the main AS-PI peak. By IEF, the respective pI values were 1.6 and 4.5. By gel filtration, the molecular weight of the main (adsorbed fraction) AS-PI was 78 000. This AS-PI strongly inhibited trypsin and to a lesser extent chymotrypsin, but exerted no inhibitory effect on plasmin. It slightly inhibited SH proteases such as papain and ficin. Immunologically, AS-PI was distinct from alpha 1-antitrypsin, alpha 1-antichymotrypsin, inter-alpha-trypsin inhibitor, antithrombin III, C1-inactivator, alpha 2-macroglobulin and alpha 2-plasmin inhibitor. The main AS-PI reacted with and was neutralized by antiurinary trypsin inhibitor serum, and on immunoelectrophoresis, had a mobility slightly cathodal to serum albumin.
mesh_terms: D000328:Adult; D001201:Ascites / Q000378:metabolism*; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D005779:Immunodiffusion; D007525:Isoelectric Focusing; D010051:Ovarian Neoplasms / Q000032:analysis*; D011480:Protease Inhibitors / Q000302:isolation & purification*; D014357:Trypsin / Q000378:metabolism
chemical_list: D011480:Protease Inhibitors; D002918:Chymotrypsin; D014357:Trypsin