Lévesque E, Beaulieu M, Green M D, Tephly T R, Bélanger A, Hum D W
Medical Research Council Group in Molecular Endocrinology, CHUL Research Center, Laval University, Québec, Canada.
Pharmacogenetics. 1997 Aug;7(4):317-25. doi: 10.1097/00008571-199708000-00007.
Genetic polymorphisms occur in many of the drug metabolizing enzymes. However, the effect of polymorphisms in the genes encoding phase II drug metabolizing UDP-glucuronosyltransferases is still undescribed, despite the many reported cases of variations in glucuronidation activities. Characterization of the UGT2B15(Y85) cDNA, which was isolated from human prostate and LNCaP cell cDNA libraries, revealed 20 nucleotide differences between UGT2B15(Y85) and the previously characterized UGT2B15 protein UGT2B15(D85). However, only one of the two variations in the coding region leads to an amino acid change from aspartic acid to a tyrosine residue at position 85. The genomic DNA of 27 subjects were analysed by direct sequencing of polymerase chain reaction (PCR) products and demonstrated that UGT2B15(D85) and UGT2B15(Y85) are encoded by variant alleles prevalent in the Caucasian population. Expression of UGT2B15(D85) and UGT2B15(Y85) in HK293 cells demonstrated similar substrate specificities. Of the 65 potential substrates tested for activity, the proteins were active on phenolic compounds, coumarins, flavonoids, drugs and steroid hormones. Both proteins displayed similar Km values of 2.2 and 2.4 microM for androstane-3alpha,17beta-diol and dihydrotestosterone, respectively. However, results suggest that UGT2B15(Y85) has a higher Vmax than UGT2B15(D85). Specific reverse transcriptase (RT)-PCR analysis revealed expression of the UGT2B15 gene in a wide range of extrahepatic tissues including the human liver, kidney, testis, mammary gland, placenta, adipose, skin, uterus, prostate and lung. The wide expression of UGT2B15 in many tissues indicates that it is a major glucuronidation enzyme in humans.
许多药物代谢酶中都存在基因多态性。然而，尽管有许多关于葡萄糖醛酸化活性变异的报道，但编码II相药物代谢UDP - 葡萄糖醛酸基转移酶的基因中的多态性影响仍未得到描述。从人前列腺和LNCaP细胞cDNA文库中分离出的UGT2B15(Y85) cDNA的特征显示，UGT2B15(Y85)与先前表征的UGT2B15蛋白UGT2B15(D85)之间存在20个核苷酸差异。然而，编码区的两个变异中只有一个导致第85位氨基酸从天冬氨酸变为酪氨酸残基。通过对聚合酶链反应（PCR）产物进行直接测序，分析了27名受试者的基因组DNA，结果表明UGT2B15(D85)和UGT2B15(Y85)由白种人群中普遍存在的变异等位基因编码。UGT2B15(D85)和UGT2B15(Y85)在HK293细胞中的表达显示出相似的底物特异性。在测试活性的65种潜在底物中，这些蛋白对酚类化合物、香豆素、黄酮类化合物、药物和甾体激素有活性。两种蛋白对雄甾烷 - 3α,17β - 二醇和二氢睾酮的Km值分别相似，为2.2和2.4 microM。然而，结果表明UGT2B15(Y85)的Vmax高于UGT2B15(D85)。特异性逆转录酶（RT）-PCR分析显示UGT2B15基因在包括人肝脏、肾脏、睾丸、乳腺、胎盘、脂肪、皮肤、子宫、前列腺和肺在内的广泛肝外组织中表达。UGT2B15在许多组织中的广泛表达表明它是人类主要的葡萄糖醛酸化酶。
