Scholze H, Löhden-Bendinger U, Müller G, Bakker-Grunwald T
University of Osnabrück, Dept. of Biochemistry, Germany.
Arch Med Res. 1992;23(2):105-8.
Amebapain, the major cysteine proteinase of E. histolytica, appears to be important both for digestion and as a cytotoxic factor. By immunocytology we established that amebapain was bound to matrix-like structures both on the cell surface and within subcellular vesicles; the amebapain co-localized with pinocytized iron oxide, suggesting that the enzyme recycles between plasma membrane and pinocytic vesicles. We conclude from these data that (i) the pinocytic vesicles in E. histolytica perform functions that in higher eukaryotes are taken over by specialized organelles such as lysosomes and cytotoxic granules, and (ii) the vesicles contain a matrix that helps retain the protease upon exocytosis of vesicle contents.
溶组织内阿米巴蛋白酶是溶组织内阿米巴的主要半胱氨酸蛋白酶，似乎对消化和作为一种细胞毒性因子都很重要。通过免疫细胞化学，我们确定溶组织内阿米巴蛋白酶与细胞表面和亚细胞小泡内的基质样结构结合；溶组织内阿米巴蛋白酶与胞饮摄入的氧化铁共定位，这表明该酶在质膜和胞饮小泡之间循环。从这些数据我们得出结论：（i）溶组织内阿米巴的胞饮小泡执行的功能在高等真核生物中由溶酶体和细胞毒性颗粒等特化细胞器承担，以及（ii）这些小泡含有一种基质，有助于在小泡内容物胞吐时保留蛋白酶。
