小柯机器人

美国德克萨斯大学Ralph J. DeBerardinis等研究人员合作完成小型组织样本中谷氨酸和天冬氨酸的综合同位素分析。这一研究成果于2023年8月22日在线发表在国际学术期刊《细胞—代谢》上。

研究人员表示，稳定同位素是评估新陈代谢的有力工具。¹³C标记可通过核磁共振（NMR）光谱或质谱（MS）来检测。质谱具有极高的灵敏度，但通常无法区分不同的¹³C位点（同位素），而核磁共振的灵敏度较低，但能报告一些同位素。

研究人员开发了一种MS方法，它能报告所有16种天冬氨酸和32种谷氨酸同位素，而所需样本量不到NMR方法的1%。与传统MS相比，该方法可区分导致天冬氨酸和谷氨酸中¹³C标记数量相同的途径，从而提高了特异性。研究人员展示了人类肿瘤内的区域代谢异质性，记录了富马酸氢化酶（FH）缺乏对人类肾癌的影响，并研究了三羧酸（TCA）循环周转和二氧化碳循环对体内同位素标记的贡献。该方法可与核磁共振或标准质谱联用，为同位素标记实验（尤其是体内实验）提供了出色的灵敏度。

附：英文原文

Title: Comprehensive isotopomer analysis of glutamate and aspartate in small tissue samples

Author: Feng Cai, Divya Bezwada, Ling Cai, Rohit Mahar, Zheng Wu, Mario C. Chang, Panayotis Pachnis, Chendong Yang, Sherwin Kelekar, Wen Gu, Bailey Brooks, Bookyung Ko, Hieu S. Vu, Thomas P. Mathews, Lauren G. Zacharias, Misty Martin-Sandoval, Duyen Do, K. Celeste Oaxaca, Eunsook S. Jin, Vitaly Margulis, Craig R. Malloy, Matthew E. Merritt, Ralph J. DeBerardinis

Issue&Volume: 2023-08-22

Abstract: Stable isotopes are powerful tools to assess metabolism. 13C labeling is detected using nuclear magnetic resonance (NMR) spectroscopy or mass spectrometry (MS). MS has excellent sensitivity but generally cannot discriminate among different 13C positions (isotopomers), whereas NMR is less sensitive but reports some isotopomers. Here, we develop an MS method that reports all 16 aspartate and 32 glutamate isotopomers while requiring less than 1% of the sample used for NMR. This method discriminates between pathways that result in the same number of 13C labels in aspartate and glutamate, providing enhanced specificity over conventional MS. We demonstrate regional metabolic heterogeneity within human tumors, document the impact of fumarate hydratase (FH) deficiency in human renal cancers, and investigate the contributions of tricarboxylic acid (TCA) cycle turnover and CO2 recycling to isotope labeling in vivo. This method can accompany NMR or standard MS to provide outstanding sensitivity in isotope-labeling experiments, particularly in vivo.

DOI: 10.1016/j.cmet.2023.07.013

Source: https://www.cell.com/cell-metabolism/fulltext/S1550-4131(23)00272-3

Cell Metabolism：《细胞—代谢》，创刊于2005年。隶属于细胞出版社，最新IF：31.373
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