SLOW MOVING PROTEINASE - ISOLATION, CHARACTERIZATION, AND IMMUNOHISTOCHEMICAL LOCALIZATION IN GASTRIC-MUCOSA
SLOW MOVING PROTEINASE - ISOLATION, CHARACTERIZATION, AND IMMUNOHISTOCHEMICAL LOCALIZATION IN GASTRIC-MUCOSA
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DOI：
10.1016/0016-5085(87)90317-9
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发表时间：
1987-07-01
期刊：
影响因子：
29.4
通讯作者：
KAY, J
中科院分区：
文献类型：
--
作者：
SAMLOFF, IM;TAGGART, RT;KAY, J
人胃黏膜含有三种免疫化学可区分的天冬氨酸蛋白酶，胃蛋白酶原I（胃蛋白酶原A），胃蛋白酶原II（胃蛋白酶原C，前胃泌素）和一种非胃蛋白酶原蛋白酶，也称为慢移蛋白酶（SMP）。SMP的性质，特别是它与另一种天冬氨酸蛋白酶组织蛋白酶D的关系，在本研究中进行了研究。从胃黏膜和人脾中分别分离到慢移蛋白酶和组织蛋白酶D。制备了兔抗各蛋白酶特异性血清。兔抗SMP不能识别组织蛋白酶D，反之，抗组织蛋白酶D也不能与SMP发生反应。免疫组织化学研究将SMP定位于胃底腺和幽门腺区域的表面上皮细胞。组织蛋白酶D主要存在于固有层和壁细胞的单核细胞中。慢移蛋白酶与两种显色底物的相互作用比组织蛋白酶d表现出相当低的Km值，两种酶之间的差异甚至更大，发现来自蛔虫的蛋白质抑制剂；SMP活性受到强烈抑制，而组织蛋白酶D活性未受影响。经变性条件下十二烷基硫酸钠-聚丙烯酰胺凝胶电泳，SMP由两个亚基组成，表观分子量分别为42,500和41,000。最后两个特性表征了一种鲜为人知的天冬氨酸蛋白酶组织蛋白酶E。我们得出结论，SMP不是组织蛋白酶D，但它可能是组织蛋白酶E。
Human gastric mucosa contains three immunochemically distinguishable aspartic proteinases, pepsinogen I (pepsinogen A), pepsinogen II (pepsinogen C, progastricsin), and a nonpepsinogen proteinase also termed slow moving proteinase (SMP). The properties of SMP, and in particular its relationship to another aspartic proteinase, cathepsin D, were examined in this study. Slow moving proteinase and cathepsin D were isolated, respectively, from gastric mucosa and human spleen. Antiserum specific to each proteinase was prepared in rabbits. Rabbit anti-SMP did not recognize cathepsin D, and conversely, anticathepsin D did not react with SMP. Immunohistochemical studies localized SMP to surface epithelial cells in both the fundic and pyloric gland areas of the stomach. In contrast, cathepsin D was found mainly in mononuclear cells in the lamina propria and in parietal cells. Slow moving proteinase exhibited considerably lower Km values for its interaction with two chromogenic substrates than did cathepsin D. An even greater distinction between the two enzymes was found with the protein inhibitor from Ascaris lumbricoides; the activity of SMP was inhibited very strongly, whereas that of cathepsin D was not affected. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis under denaturing conditions, SMP consisted of two subunits with apparent molecular weights of 42,500 and 41,000. The last two properties characterize a less-well-known aspartic proteinase, cathepsin E. We conclude that SMP is not cathepsin D, but that it may be cathepsin E.