Burchell B, Ebner T, Baird S, Bin Senafi S, Clarke D, Brierley C, Sutherland L
Department of Biochemical Medicine, Nimewells Medical School, University of Dundee, Scotland.
Environ Health Perspect. 1994 Nov;102 Suppl 9(Suppl 9):19-23. doi: 10.1289/ehp.94102s919.
Five cloned human hepatic UDP-glucuronosyltransferase (UGT) cDNAs were stably expressed in tissue culture cell lines. More than 100 drugs and xenobiotics were used as substrates for glucuronidation catalyzed by the cloned human transferases to determine the chemical structures accepted as substrates. UGT-HP1 exhibited a limited substrate specificity for planar phenolic compounds, whereas UGT-HP4 was more accepting of nonplanar phenols, anthraquinones, flavones, alphatic alcohols, aromatic carboxylic acids, steroids and many drugs of varied structure. UGT-HP3 (bilirubin UGT) catalyzed the glucuronidation of ethinylestradiol. UGT-H6 and UGT-H25 (steroid/bile acid UGTs) also catalyzed the glucuronidation of some xenobiotics. Levels of UGT-HP4 activity towards some substrates were sufficient to allow determination of kinetic parameters for the enzyme reaction. Further, metabolism of drugs could be studied by addition to the recombinant cell lines in culture and extraction of the media allowed analysis of glucuronide formation. The protection afforded against cytotoxic drugs was observed. The data presented here demonstrate the potential of using these recombinant cell lines for investigation of phase II metabolism by human UGTs and subtle differences in protein structure which affect their specificity.
五个克隆的人肝UDP-葡萄糖醛酸转移酶（UGT）cDNA在组织培养细胞系中稳定表达。超过100种药物和外源性物质被用作克隆的人转移酶催化葡萄糖醛酸化反应的底物，以确定被接受为底物的化学结构。UGT-HP1对平面酚类化合物表现出有限的底物特异性，而UGT-HP4更易接受非平面酚类、蒽醌、黄酮、脂肪醇、芳香羧酸、类固醇以及许多结构各异的药物。UGT-HP3（胆红素UGT）催化乙炔雌二醇的葡萄糖醛酸化反应。UGT-H6和UGT-H25（类固醇/胆汁酸UGT）也催化一些外源性物质的葡萄糖醛酸化反应。UGT-HP4对某些底物的活性水平足以确定酶反应的动力学参数。此外，通过向培养的重组细胞系中添加药物并对培养基进行提取，可以研究药物的代谢，从而分析葡萄糖醛酸苷的形成。观察到了对细胞毒性药物的保护作用。此处呈现的数据证明了利用这些重组细胞系研究人UGT介导的II相代谢以及影响其特异性的蛋白质结构细微差异的潜力。
