von Meyerinck L, Coffman B L, Green M D, Kirkpatrick R B, Schmoldt A, Tephly T R
Drug Metab Dispos. 1985 Nov-Dec;13(6):700-4.
Glucuronidation of digitoxigenin-monodigitoxoside was investigated in liver microsomes from spironolactone-induced male Wistar rats. Isolation of a specific digitoxigenin-monodigitoxoside UDP-glucuronosyltransferase was possible utilizing chromatofocusing chromatography with a gradient from pH 10.1 to 8.0 after solubilizing the microsomal protein with the nonionic detergent Emulgen 911. The digitoxigenin-monodigitoxoside UDP-glucuronosyltransferase was further purified using UDP-hexanolamine Sepharose 4B affinity chromatography. The highly purified (75-fold) enzyme showed activity toward digitoxigenin-monodigitoxoside and slight activity toward digitoxigenin-bisdigitoxoside, whereas digitoxin and substrates for p-nitrophenol, 17 beta-OH steroid, and 3 alpha-OH steroid UDP-glucuronosyltransferases were not glucuronidated. In addition, bilirubin, morphine, estrone, 4-hydroxybiphenyl, and aromatic amines were not glucuronidated by this protein. These results strongly confirm the presence of a form of UDP-glucuronosyltransferase, which is highly specific for the glucuronidation of digitoxigenin-monodigitoxoside.
在螺内酯诱导的雄性Wistar大鼠的肝微粒体中研究了洋地黄毒苷元 - 单洋地黄毒糖苷的葡萄糖醛酸化作用。在用非离子去污剂乳化剂911溶解微粒体蛋白后，利用从pH 10.1到8.0梯度的聚焦层析法，有可能分离出一种特异性的洋地黄毒苷元 - 单洋地黄毒糖苷UDP - 葡萄糖醛酸基转移酶。使用UDP - 己醇胺琼脂糖4B亲和层析法进一步纯化洋地黄毒苷元 - 单洋地黄毒糖苷UDP - 葡萄糖醛酸基转移酶。高度纯化（75倍）的酶对洋地黄毒苷元 - 单洋地黄毒糖苷表现出活性，对洋地黄毒苷元 - 双洋地黄毒糖苷表现出轻微活性，而洋地黄毒苷以及对硝基苯酚、17β - OH类固醇和3α - OH类固醇UDP - 葡萄糖醛酸基转移酶的底物均未发生葡萄糖醛酸化。此外，胆红素、吗啡、雌酮、4 - 羟基联苯和芳香胺也不会被该蛋白葡萄糖醛酸化。这些结果有力地证实了存在一种UDP - 葡萄糖醛酸基转移酶形式，它对洋地黄毒苷元 - 单洋地黄毒糖苷的葡萄糖醛酸化具有高度特异性。
