Chowdhury J R, Novikoff P M, Chowdhury N R, Novikoff A B
Proc Natl Acad Sci U S A. 1985 May;82(9):2990-4. doi: 10.1073/pnas.82.9.2990.
UDPglucuronosyltransferase [UDPglucuronate beta-D-glucuronosyltransferase (acceptor-unspecific), EC 2.4.1.17] is a group of enzymes with distinct but partially overlapping substrate specificity. A rabbit antiserum raised against one purified rat liver UDPglycuronosyltransferase isoform was specific for UDPglucuronosyltransferase and recognized all transferase isoforms by immunodiffusion or immunotransblot analysis. The transferase activity toward all substrates was immunoabsorbed from solubilized rat liver microsomes by IgG purified from the antiserum. The purified IgG was used for immunocytochemical localization of UDP-glucuronosyltransferase in rat liver, jejunum, kidney, and adrenal gland. In the liver, UDPglucuronosyltransferase was present exclusively in hepatocytes and was uniformly distributed within all zones of the hepatic lobule. In the jejunum, the transferase was present exclusively in the epithelial cells and showed a progressive increase in concentration from the crypt to the villar tip. In the kidney, the greatest concentration of the transferase was observed in the epithelial cells of the proximal convoluted tubule. Adrenal medullary cells showed intense immunocytochemical staining; the zona glomerulosa and the zona reticularis of the adrenal cortex were more intensely stained than the zona fasciculata. By light microscopy, UDPglucuronosyltransferase was found in the endoplasmic reticulum and nuclear envelope of all the four organs; this was confirmed in the hepatocyte by electron microscopy. The transferase was not observed in mitochondria, Golgi apparatus, lysosomes, peroxisomes, and plasma membrane, even after 3- to 4-fold induction of various substrate-specific UDPglucuronosyltransferase activities.
UDP葡糖醛酸基转移酶[UDP葡糖醛酸β-D-葡糖醛酸基转移酶（受体非特异性），EC 2.4.1.17]是一组具有不同但部分重叠底物特异性的酶。针对一种纯化的大鼠肝脏UDP葡糖醛酸基转移酶同工型产生的兔抗血清对UDP葡糖醛酸基转移酶具有特异性，并通过免疫扩散或免疫印迹分析识别所有转移酶同工型。从抗血清中纯化的IgG从溶解的大鼠肝脏微粒体中免疫吸附了对所有底物的转移酶活性。纯化的IgG用于大鼠肝脏、空肠、肾脏和肾上腺中UDP-葡糖醛酸基转移酶的免疫细胞化学定位。在肝脏中，UDP葡糖醛酸基转移酶仅存在于肝细胞中，并均匀分布在肝小叶的所有区域。在空肠中，转移酶仅存在于上皮细胞中，并且从隐窝到绒毛尖端浓度逐渐增加。在肾脏中，在近端曲管的上皮细胞中观察到转移酶的最高浓度。肾上腺髓质细胞显示强烈的免疫细胞化学染色；肾上腺皮质的球状带和网状带比束状带染色更强烈。通过光学显微镜，在所有四个器官的内质网和核膜中发现了UDP葡糖醛酸基转移酶；通过电子显微镜在肝细胞中得到了证实。即使在各种底物特异性UDP葡糖醛酸基转移酶活性诱导3至4倍后，在线粒体、高尔基体、溶酶体、过氧化物酶体和质膜中也未观察到转移酶。
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