UDP-Glucuronosyltransferase 1A1 Is the Principal Enzyme Responsible for Etoposide Glucuronidation in Human Liver and Intestinal Microsomes: Structural Characterization of Phenolic and Alcoholic Glucuronides of Etoposide and Estimation of Enzyme Kinetics

葡萄糖醛酸化 化学 微粒体 依托泊苷 葡萄糖醛酸 微粒体 生物化学 新陈代谢 色谱法 立体化学 化疗 生物 遗传学
作者
Zhiming Wen,Melanie N. Tallman,Shazia Ali,Philip C. Smith
出处
期刊:Drug Metabolism and Disposition [American Society for Pharmacology and Experimental Therapeutics]
卷期号:35 (3): 371-380 被引量:77
标识
DOI:10.1124/dmd.106.012732
摘要

Etoposide, an important anticancer agent, undergoes glucuronidation both in vitro and in vivo. In this study, three isomeric glucuronides of etoposide, including one phenolic (EPG) and two alcoholic glucuronides (EAG1 and EAG2), were biosynthesized in vitro with human liver microsomes (HLMs), and identified by liquid chromatography-electrospray ionization-mass spectrometry and confirmed by β-glucuronidase cleavage. In vitro UDP-glucuronosyltransferase (UGT) reaction screening with 12 recombinant human UGTs demonstrated that etoposide glucuronidation is mainly catalyzed by UGT1A1. Although UGT1A8 and 1A3 also catalyzed the glucuronidation of etoposide, their activities were approximately 10 and 1% of UGT1A1. Enzyme kinetic study indicated that the predominant form of etoposide glucuronide in HLMs and human intestinal microsomes (HIMs) was EPG, whereas EAG1 and EAG2 were the minor metabolites, with approximately an 8 to 10% glucuronidation rate of EPG. For the formation of EPG, the Vmax of HLMs (110 pmol/min/mg protein) was very similar to that of recombinant UGT1A1 (124 pmol/min/mg protein), whereas the Vmax of HIMs (54.4 pmol/min/mg protein) was 2-fold lower than those of HIMs and UGT1A1. The Km values of HLMs (530 μM) and HIMs (608 μM) were 2-fold higher than that of UGT1A1 (285 μM). The Vmax/Km values for the formation of EPG were 0.21 and 0.09 μl/min/mg protein for HLMs and HIMs, respectively. The data indicated that UGT1A1 is principally responsible for the formation of etoposide glucuronides, mainly in the form of phenolic glucuronide, suggesting that etoposide can be used as a highly selective probe substrate for human UGT1A1 in vitro.
最长约 10秒,即可获得该文献文件

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
PDF的下载单位、IP信息已删除 (2025-6-4)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
李爱国应助Kevin采纳,获得10
1秒前
1秒前
drimary发布了新的文献求助10
1秒前
2秒前
小马甲应助Young采纳,获得10
2秒前
zhaoyali完成签到,获得积分20
2秒前
明哲派发布了新的文献求助30
2秒前
4秒前
MADKAI发布了新的文献求助10
4秒前
在水一方应助Joff_W采纳,获得30
4秒前
4秒前
yang发布了新的文献求助20
5秒前
荷兰香猪发布了新的文献求助10
5秒前
苹果笑寒发布了新的文献求助10
6秒前
6秒前
二喵完成签到 ,获得积分10
7秒前
高兴藏花完成签到 ,获得积分20
7秒前
余小鱼完成签到,获得积分10
7秒前
zhaoyali发布了新的文献求助10
8秒前
轻松的璐啦啦完成签到 ,获得积分10
8秒前
8秒前
8秒前
8秒前
8秒前
陈茜应助勤劳小海豚采纳,获得10
9秒前
归尘发布了新的文献求助10
9秒前
9秒前
瑶瑶酱完成签到,获得积分10
9秒前
刘浩然发布了新的文献求助10
9秒前
rtcpu完成签到,获得积分10
9秒前
10秒前
开心孤容完成签到,获得积分10
10秒前
10秒前
10秒前
10秒前
11秒前
MADKAI发布了新的文献求助10
11秒前
科研通AI2S应助phd_cheng采纳,获得10
11秒前
shgd完成签到,获得积分10
12秒前
Orange应助szn采纳,获得10
12秒前
高分求助中
A new approach to the extrapolation of accelerated life test data 1000
ACSM’s Guidelines for Exercise Testing and Prescription, 12th edition 500
Picture Books with Same-sex Parented Families: Unintentional Censorship 500
Nucleophilic substitution in azasydnone-modified dinitroanisoles 500
不知道标题是什么 500
A Preliminary Study on Correlation Between Independent Components of Facial Thermal Images and Subjective Assessment of Chronic Stress 500
Phylogenetic study of the order Polydesmida (Myriapoda: Diplopoda) 360
热门求助领域 (近24小时)
化学 材料科学 医学 生物 工程类 有机化学 生物化学 物理 内科学 纳米技术 计算机科学 化学工程 复合材料 遗传学 基因 物理化学 催化作用 冶金 细胞生物学 免疫学
热门帖子
关注 科研通微信公众号,转发送积分 3971125
求助须知:如何正确求助?哪些是违规求助? 3515824
关于积分的说明 11179811
捐赠科研通 3250971
什么是DOI,文献DOI怎么找? 1795610
邀请新用户注册赠送积分活动 875897
科研通“疑难数据库(出版商)”最低求助积分说明 805207