Strawser L D, Touster O
J Biol Chem. 1979 May 25;254(10):3716-9.
A binding protein with apparent specificity for beta-glucuronidase has been partially purified from a Triton X-100 extract of rat liver microsomes by affinity chromatography on glucuronidase-Sepharose 2B. It appears that once removed from the membrane, this binding protein self-aggregates to form large macromolecular complexes. With the use of polyacrylamide gel electrophoretic and sucrose density gradient ultracentrifugation assays to monitor the conversion of glucuronidase tetramer to a very high molecular weight complex, it was shown that the binding activity is heatlabile and protease-sensitive. However, binding activity is not influenced by salts, carbohydrates, other proteins or glycoproteins, or by extensive periodate oxidation of beta-glucuronidase, nor does binding occur with any other protein tested. The binding protein does not discriminate against any form of beta-glucuronidase from any rat organ tested. However, the binding protein does show organ localization, being present in the liver and kidney but not the spleen. The possible relationship of this binding protein to egasyn, a membrane protein which stabilizes beta-glucuronidase in mouse liver endoplasmic reticulum, is discussed.
通过在葡糖醛酸酶-琼脂糖2B上进行亲和层析，已从大鼠肝脏微粒体的Triton X-100提取物中部分纯化出一种对β-葡糖醛酸酶具有明显特异性的结合蛋白。似乎一旦从膜上移除，这种结合蛋白就会自我聚集形成大分子复合物。通过使用聚丙烯酰胺凝胶电泳和蔗糖密度梯度超速离心分析来监测葡糖醛酸酶四聚体向非常高分子量复合物的转化，结果表明结合活性对热不稳定且对蛋白酶敏感。然而，结合活性不受盐、碳水化合物、其他蛋白质或糖蛋白的影响，也不受β-葡糖醛酸酶广泛的高碘酸盐氧化的影响，并且与所测试的任何其他蛋白质都不发生结合。该结合蛋白对来自任何所测试大鼠器官的任何形式的β-葡糖醛酸酶都没有选择性。然而，该结合蛋白确实表现出器官定位，存在于肝脏和肾脏中，但不存在于脾脏中。本文讨论了这种结合蛋白与egasyn（一种在小鼠肝脏内质网中稳定β-葡糖醛酸酶的膜蛋白）之间可能的关系。
