Expression of cytosolic β-glucosidase in guinea pig liver cells
Expression of cytosolic β-glucosidase in guinea pig liver cells
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DOI：
10.1002/hep.510280121
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发表时间：
1998-07-01
期刊：
影响因子：
13.5
通讯作者：
Johnston, DE
中科院分区：
文献类型：
--
作者：
Hays, WS;Wheeler, DE;Johnston, DE
哺乳动物肝脏的胞质β-葡糖苷酶参与植物糖苷的代谢转化，如与毒性综合征的发展相关的鹿豆碱和苦杏仁苷。我们调查了哪些告诉类型在豚鼠肝脏中表达胞质β-葡萄糖苷酶，并表征了这种酶对培养细胞和组织切片中芳香糖苷水解的贡献。细胞溶质β-葡萄糖苷酶在肝细胞中表达，而在枯否细胞或内皮细胞中不表达，这通过酶特异性活性和肝细胞提取物的蛋白质印迹法确定。使用荧光β-葡糖苷酶底物试卤灵β-D-葡糖苷可视化细胞内β-葡糖苷酶活性，并显示其由使用抑制剂Conduritol β-环氧化物和二硝基苯酚-2-脱氧-2-氟-β-D-吡喃葡萄糖苷（DNP 2FGlc）的细胞溶质β-葡糖苷酶引起。用试卤灵β-葡萄糖苷染色新鲜肝切片，显示胞质β-葡萄糖苷酶在所有肝细胞中表达，没有显著的门-中央梯度。这些数据表明胞质β-葡萄糖苷酶是肝细胞特异性酶，并支持肝中胞质β-葡萄糖苷酶的功能是水解肠吸收的小葡萄糖苷的假设。此外，CCl（4）对培养肝细胞的毒性损伤导致细胞溶质β-葡萄糖苷酶与肝细胞标志酶丙氨酸转氨酶和乳酸脱氢酶平行释放。这表明肝损伤动物模型中细胞溶质β-葡萄糖苷酶血清水平的急性升高可能反映了肝细胞的直接损伤。
The cytosolic beta-glucosidase of mammalian liver has been implicated in the metabolic transformation of plant glycosides, such as vicine and amygdalin, which are associated with the development of toxic syndromes. We investigated which tell types express cytosolic beta-glucosidase in guinea pig liver, and characterized the contribution of this enzyme to the hydrolysis of aromatic glucosides in cultured cells and in tissue slices. Cytosolic beta-glucosidase was expressed in hepatocytes and not in Kupffer or endothelial cells as determined by enzyme-specific activity and Western blots of liver cell extracts. Intracellular beta-glucosidase activity was visualized using the fluorescent beta-glucosidase substrate, resorufin beta-D-glucoside, and shown to be caused by the cytosolic beta-glucosidase using the inhibitors, conduritol beta-epoxide and dinitrophenol-2-deoxy-2-fluoro-beta-D-glucop ranoside (DNP2FGlc). Staining of fresh liver slices with resorufin beta-glucoside revealed that cytosolic beta-glucosidase is expressed in all hepatocytes, with no significant portal-central gradient, These data indicate that cytosolic beta-glucosidase is a hepatocyte-specific enzyme, and support the hypothesis that cytosolic beta-glucosidase in the liver functions to hydrolyze small glucosides absorbed by the intestine. Furthermore, toxic injury to cultured hepatocytes by CCl(4) resulted in release of cytosolic beta-glucosidase in parallel with the hepatocyte marker enzymes alanine transaminase and lactate dehydrogenase. This suggests that acute increases in serum levels of cytosolic beta-glucosidase in animal models of liver injury may reflect direct injury of hepatocytes.