Leeming Michael G, Isaac Andrew P, Pope Bernard J, Cranswick Noel, Wright Christine E, Ziogas James, O'Hair Richard A J, Donald William A
†School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, 30 Flemington Road, Melbourne, Victoria 3010, Australia.
‡Victorian Life Sciences Computation Initiative, University of Melbourne, 187 Grattan Street, Carlton, Victoria 3010, Australia.
Anal Chem. 2015 Apr 21;87(8):4104-9. doi: 10.1021/ac504767d. Epub 2015 Apr 8.
The metabolic fate of a compound can often determine the success of a new drug lead. Thus, significant effort is directed toward identifying the metabolites formed from a given molecule. Here, an automated and nontargeted procedure is introduced for detecting drug metabolites without authentic metabolite standards via the use of stable isotope labeling, liquid chromatography mass spectrometry (LC/MS), and high-performance computing. LC/MS of blood plasma extracts from rats that were administered a 1:1 mixture of acetaminophen (APAP) and (13)C6-APAP resulted in mass spectra that contained "twin" ions for drug metabolites that were not detected in control spectra (i.e., no APAP administered). Because of the development of a program (high-resolution twin-ion metabolite extraction; HiTIME) that can identify twin-ions in high-resolution mass spectra without centroiding (i.e., reduction of mass spectral peaks to single data points), 9 doublets corresponding to APAP metabolites were identified. This is nearly twice that obtained by use of existing programs that make use of centroiding to reduce computational cost under these conditions with a quadrupole time-of-flight mass spectrometer. By a manual search for all reported APAP metabolite ions, no additional twin-ion signals were assigned. These data indicate that all the major metabolites of APAP and multiple low-abundance metabolites (e.g., acetaminophen hydroxy- and methoxysulfate) that are rarely reported were detected. This methodology can be used to detect drug metabolites without prior knowledge of their identity. HiTIME is freely available from https://github.com/bjpop/HiTIME .
一种化合物的代谢命运往往能决定一种新药先导物的成败。因此，人们投入了大量精力来鉴定由给定分子形成的代谢产物。在此，介绍一种自动化的非靶向程序，通过使用稳定同位素标记、液相色谱质谱联用（LC/MS）和高性能计算，在没有真实代谢产物标准品的情况下检测药物代谢产物。对给予对乙酰氨基酚（APAP）和（13）C6 - APAP 1:1混合物的大鼠血浆提取物进行LC/MS分析，得到的质谱图中含有药物代谢产物的“孪生”离子，而在对照质谱图（即未给予APAP）中未检测到。由于开发了一个程序（高分辨率孪生离子代谢产物提取；HiTIME），该程序可以在不进行质心化（即将质谱峰简化为单个数据点）的情况下识别高分辨率质谱图中的孪生离子，从而鉴定出9个与APAP代谢产物对应的双峰。这几乎是在这些条件下使用四极杆飞行时间质谱仪、利用质心化来降低计算成本的现有程序所得到结果的两倍。通过手动搜索所有已报道的APAP代谢产物离子，未发现其他孪生离子信号。这些数据表明，APAP的所有主要代谢产物以及多种低丰度代谢产物（例如对乙酰氨基酚羟基硫酸盐和甲氧基硫酸盐）均被检测到，而这些低丰度代谢产物很少被报道。这种方法可用于在不预先了解药物代谢产物身份的情况下进行检测。HiTIME可从https://github.com/bjpop/HiTIME免费获取。
