The Human UDP-Glucuronosyltransferase UGT2A1 and UGT2A2 Enzymes Are Highly Active in Bile Acid Glucuronidation
摘要:
胆汁酸(BA)是脂质、葡萄糖和胆固醇稳态的重要调节剂,但在胆汁淤积的肝脏中会产生细胞毒性。由UDP-葡萄糖醛酸转移酶(UGT)催化的葡萄糖醛酸化是BA解毒过程中一个重要的药理过程。本研究对2A亚家族中研究较少的人UGTs的BA结合活性进行了表征:UGT2A1、2A2和2A3。在杆状病毒感染的昆虫细胞中表达的重组UGT2A对六种主要胆汁酸的葡萄糖醛酸化进行了检测:鹅去氧胆酸(CDCA)、胆酸(CA)、石胆酸(LCA)、脱氧胆酸(DCA)、牛胆酸(HCA)和猪去氧胆酸(HDCA)。UGT2A3对所有测试的BA底物表现出可检测但非常低的活性。UGT2A1在形成LCA-3和LCA-24G、CDCA-24、DCA-24、HCA-24和HDCA-24G方面非常高效,而UGT2A2是形成CA-24G和CDCA-24G的最活跃的酶,并且能够产生HDCA-6G、HDCA-24G、LCA-24G和HCA-24G。UGT2A1的K m
CYP3A Specifically Catalyzes 1 -Hydroxylation of Deoxycholic Acid: Characterization and Enzymatic Synthesis of a Potential Novel Urinary Biomarker for CYP3A Activity
作者:M. A. Hayes、X.-Q. Li、G. Gronberg、U. Diczfalusy、T. B. Andersson
DOI:10.1124/dmd.116.070805
日期:2016.8.2
The endogenous bile acid metabolite 1β-hydroxy-deoxycholic acid (1β-OH-DCA) excreted in human urine may be used as a sensitive CYP3A biomarker in drug development reflecting in vivo CYP3A activity. An efficient and stereospecificenzymaticsynthesis of 1β-OH-DCA was developed using a Bacillus megaterium (BM3) cytochrome P450 (P450) mutant, and its structure was confirmed by nuclear magnetic resonance
The bile acid-inducible baiB gene from Eubacterium sp. strain VPI 12708 encodes a bile acid-coenzyme A ligase
作者:D H Mallonee、J L Adams、P B Hylemon
DOI:10.1128/jb.174.7.2065-2071.1992
日期:1992.4
baiB gene from Eubacteriumsp. strain VPI12708 was previously cloned, sequenced, and shown to be part of a large bileacid-inducible operon encoding polypeptides believed to be involved in bile acid 7 alpha-dehydroxylation. In the present study, the baiB gene was subcloned and expressed in Escherichiacoli and shown to encode a bile acid-coenzyme A (CoA) ligase. This ligase required a C-24 bile acid
A biosynthetic pathway for a prominent class of microbiota-derived bile acids
作者:A Sloan Devlin、Michael A Fischbach
DOI:10.1038/nchembio.1864
日期:2015.9
A bioinformatic and phylogenetic search identifies five enzymes involved in the conversion of DCA to isoDCA in the bacterial bile acid biosynthetic pathway. An investigation of the biological roles of bile acids defines a mutualism between the producer R. gnavus and the nonproducer Bacteroides. The gut bile acid pool is millimolar in concentration, varies widely in composition among individuals and is linked to metabolic disease and cancer. Although these molecules are derived almost exclusively from the microbiota, remarkably little is known about which bacterial species and genes are responsible for their biosynthesis. Here we report a biosynthetic pathway for the second most abundant class in the gut, 3β-hydroxy(iso)-bile acids, whose levels exceed 300 μM in some humans and are absent in others. We show, for the first time, that isoâbile acids are produced by Ruminococcus gnavus, a far more abundant commensal than previously known producers, and that the isoâbile acid pathway detoxifies deoxycholic acid and thus favors the growth of the keystone genus Bacteroides. By revealing the biosynthetic genes for an abundant class of bile acids, our work sets the stage for predicting and rationally altering the composition of the bile acid pool.
通过生物信息学和系统发生学搜索,确定了在细菌胆汁酸生物合成途径中参与将二氯苯甲醚(DCA)转化为异二氯苯甲醚(isoDCA)的五种酶。对胆汁酸生物学作用的研究确定了生产者 R. gnavus 和非生产者 Bacteroides 之间的互作关系。 肠道胆汁酸池的浓度为毫摩尔,个体之间的组成差异很大,并且与代谢疾病和癌症有关。虽然这些分子几乎全部来自微生物群,但人们对负责其生物合成的细菌种类和基因知之甚少。在这里,我们报告了肠道中含量第二高的3δ²-羟基(异)-胆酸的生物合成途径,在一些人体内,3δ²-羟基(异)-胆酸的含量超过300 ¼M,而在另一些人体内则没有。我们首次发现gnavus反刍球菌能产生异胆酸,它是一种比以前已知的生产者更丰富的共生菌,异胆酸途径能解毒脱氧胆酸,从而有利于关键菌属Bacteroides的生长。通过揭示一类丰富胆汁酸的生物合成基因,我们的工作为预测和合理改变胆汁酸库的组成奠定了基础。