Rhoads M L, Romanowski R D, Doherty R F, Stewart K K
J Biol Chem. 1978 Mar 10;253(5):1639-42.
Three proteinase inhibitors designated as I, II, and III were isolated from the excretory gland cells of the swine kidney worm, Stephanurus dentatus. The inhibitors, which were trichloroacetic acid-soluble, were purified by affinity chromatography and ion exchange chromatography. The homogeneity of each inhibitor was shown by polyacrylamide gel electrophoresis and electrofocusing. The molecular weights of the inhibitors estimated by sodium dodecyl sulfate gel electrophoresis fell within a limited range of 9300 to 9700, and the isoelectric points were 6.45, 6.20, and 5.34 for Inhibitors I, II, and III, respectively. The inhibitors formed complexes with trypsin having apparent dissociation constants (Ki) of 2.9 X 10(-11), 7.6 X 10(-11), and 6.4 X 10(-11) M, respectively. Each inhibitor inhibits the esterolytic and proteolytic activities of both trypsin and chymotrypsin. A proteinase inhibitor present in the reproductive organs, intestines, body walls, and esophagi was identical with Inhibitor II found in the excretory gland cells. Culture medium collected after 24-h incubation with adult worms contained the same three inhibitors as the excretory gland cells. These data suggest that the gland cells may secrete the inhibitors internally and externally.
从猪肾虫（齿冠线虫）的排泄腺细胞中分离出三种蛋白酶抑制剂，分别命名为抑制剂I、II和III。这些可溶于三氯乙酸的抑制剂通过亲和层析和离子交换层析进行纯化。通过聚丙烯酰胺凝胶电泳和等电聚焦显示了每种抑制剂的均一性。通过十二烷基硫酸钠凝胶电泳估计的抑制剂分子量在9300至9700的有限范围内，抑制剂I、II和III的等电点分别为6.45、6.20和5.34。这些抑制剂与胰蛋白酶形成复合物，其表观解离常数（Ki）分别为2.9×10⁻¹¹、7.6×10⁻¹¹和6.4×10⁻¹¹M。每种抑制剂都抑制胰蛋白酶和胰凝乳蛋白酶的酯解和蛋白水解活性。存在于生殖器官、肠道、体壁和食管中的一种蛋白酶抑制剂与在排泄腺细胞中发现的抑制剂II相同。与成虫孵育24小时后收集的培养基中含有与排泄腺细胞相同的三种抑制剂。这些数据表明，腺细胞可能在内部和外部分泌抑制剂。
