Vicente-Muñoz Sara, Lin Penghui, Fan Teresa W-M, Lane Andrew N
Center for Environmental and Systems Biochemistry, Markey Cancer Center, and Dept. of Toxicology & Cancer Biology, University of Kentucky, 789 S. Limestone Street, Lexington, Kentucky 40536, United States.
Anal Chem. 2021 May 4;93(17):6629-6637. doi: 10.1021/acs.analchem.0c04220. Epub 2021 Apr 21.
A substantial fraction of common metabolites contains carboxyl functional groups. Their C isotopomer analysis by nuclear magnetic resonance (NMR) is hampered by the low sensitivity of the C nucleus, the slow longitudinal relaxation for the lack of an attached proton, and the relatively low chemical shift dispersion of carboxylates. Chemoselective (CS) derivatization is a means of tagging compounds in a complex mixture via a specific functional group. N-cholamine has been shown to be a useful CS agent for carboxylates, producing a peptide bond that can be detected via N-attached H with high sensitivity in heteronuclear single quantum coherence experiments. Here, we report an improved method of derivatization and show how C-enrichment at the carboxylate and/or the adjacent carbon can be determined via one- and two-bond coupling of the carbons adjacent to the cholamine N atom in the derivatives. We have applied this method for the determination of C isotopomer distribution in the extracts of A549 cell culture and liver tissue from a patient-derived xenograft mouse.
相当一部分常见代谢物含有羧基官能团。通过核磁共振（NMR）对其碳同位素异构体进行分析时，由于碳原子核灵敏度低、缺乏连接质子导致纵向弛豫缓慢以及羧酸盐的化学位移分散相对较低而受到阻碍。化学选择性（CS）衍生化是一种通过特定官能团标记复杂混合物中化合物的方法。N-胆胺已被证明是一种用于羧酸盐的有用CS试剂，可形成肽键，该肽键可在异核单量子相干实验中通过与N相连的氢以高灵敏度进行检测。在此，我们报告了一种改进的衍生化方法，并展示了如何通过衍生物中与胆胺N原子相邻的碳的一键和两键耦合来确定羧酸盐和/或相邻碳处的碳富集情况。我们已将此方法应用于测定来自患者来源的异种移植小鼠的A549细胞培养物和肝组织提取物中的碳同位素异构体分布。
