Centre of Biomedical Magnetic Resonance, SGPGIMS Campus, Raibarelli Road, Lucknow-226014, India.
Anal Chem. 2009 Dec 15;81(24):10232-8. doi: 10.1021/ac902405z.
We present a general scheme for metabolite quantification from a two-dimensional (2D) (1)H-(13)C heteronuclear single quantum correlation (HSQC) nuclear magnetic resonance (NMR) experiment of body fluids observed in natural abundance. The scheme of quantification from 2D HSQC spectra consists of measurement of relaxation parameters of proton resonances, such as T(1) and T(2) of the metabolites and (1)H-(13)C heteronuclear J-coupling for accurate quantification. The measured cross-peak volume from 2D HSQC NMR spectra is multiplied by a calculated correction factor (which depends upon two-dimensional NMR experimental parameters and relaxation parameters) to measure accurate quantification of the metabolite. The correction factor is theoretically derived from the solution of the Bloch equation and product operator formalism. The accuracy of the scheme is tested on a solution containing a mixture of amino acids of known concentration. For human urine samples, the accuracy of the method for measuring the concentration of various metabolites was tested with spike-in experiments. The scheme is general in nature and can be applied to any other body fluid samples for metabonomic studies. We also test the measured cross-peak volume of various metabolites from 2D (1)H-(13)C HSQC NMR spectra of human urine samples for clustering analysis with scatter plots, making the scheme complete for metabolic profiling.
我们提出了一种从天然丰度下观察到的体液二维 (1)H-(13)C 异核单量子相关 (HSQC) 核磁共振 (NMR) 实验中定量代谢物的通用方案。该 2D HSQC 谱定量方案包括测量质子共振的弛豫参数，如代谢物的 T(1)和 T(2)以及 (1)H-(13)C 异核 J 耦合，以实现准确的定量。从 2D HSQC NMR 谱测量的交叉峰体积乘以计算出的校正因子（取决于二维 NMR 实验参数和弛豫参数），以测量代谢物的准确定量。校正因子是从 Bloch 方程和乘积算子形式的解理论推导出来的。该方案的准确性在含有已知浓度氨基酸混合物的溶液中进行了测试。对于人尿液样本，使用加标实验测试了该方法测量各种代谢物浓度的准确性。该方案具有普遍性，可应用于任何其他用于代谢组学研究的体液样本。我们还对人尿液样本的二维 (1)H-(13)C HSQC NMR 谱中各种代谢物的测量交叉峰体积进行了聚类分析，用散点图表示，使代谢谱分析方案完整。
