Identification and Characterization of Trypsin, Chymotrypsin and Elastase Inhibitors in Porcine Serum

Abstract

Characterization of the trypsin-, chymotrypsin- and elastase-inhibiting properties of porcine serum was carried out by gel filtration on Ultrogel, AcA 44, and agarose gel electrophoresis with subsequent processing for protease-inhibiting activity. By allowing the fractions obtained from gel filtration to react with antibodies to porcine serum protease inhibitors, the specific inhibiting properties of these inhibitor molecules were identified. At least 6 protease inhibitors were identified and partially characterized in porcine serum. Two .alpha.2-macroglobulins (.alpha.2 Mf and .alpha.2 Ms), homologs to human .alpha.2-macroglobulin, with slightly different electrophoretic mobilities exhibit trypsin, chymotrypsin and elastase inhibiting activity. .alpha.1-Protease inhibitor (MW 51,000), a homolog to human .alpha.1-protease inhibitor (.alpha.1-antitrypsin), also showed trypsin-, chymotrypsin- and elastase-inhibiting properties. Inter-.alpha.-trypsin inhibitor (MW 162,000 and 129,000), a porcine serum counterpart to human inter-.alpha.-trypsin inhibitor, showed trypsin- and chymotrypsin-inhibiting properties. A specific trypsin inhibitor, .alpha.2-antitrypsin (MW 58,000), and a specific elastase inhibitor, .beta.-elastase inhibitor, were characterized in porcine serum, and these seem to have no counterparts in human serum.