Microwave-Assisted 18O-Labeling of Proteins Catalyzed by Formic Acid
Microwave-Assisted 18O-Labeling of Proteins Catalyzed by Formic Acid
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DOI：
10.1021/ac101888f
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发表时间：
2010-11-01
影响因子：
7.4
通讯作者：
Cai, Zongwei
中科院分区：
文献类型：
--
作者：
Liu, Ning;Wu, Hanzhi;Cai, Zongwei
氧交换可能发生在酸催化的羧基上。然而，在室温下，这个反应至少需要几天时间。长时间的交换反应常常阻碍其在蛋白质分析中的应用。本研究建立了一种利用微波辅助酸解的O-18标记方法。蛋白质样品在含有2.5%甲酸的O-16/O-18(1：1)水中溶解后，在微波辐射下进行处理。LC-MS/MS分析表明，谷氨酸、天冬氨酸和C端残基的羧基上的氧可以在不到1.5min的时间内与O-18有效地交换。反向交换的速度如此之慢，以至于在高效液相色谱运行期间没有发现可检测到的反向交换。
Oxygen exchange may occur at carboxyl groups catalyzed by acid. The reaction, however, takes at least several days at room temperature. The long-time exchanging reaction often prevents its application from protein analysis. In this study, an O-18-labeling method utilizing microwave-assisted acid hydrolysis was developed. After being dissolved in O-16/O-18 (1:1) water containing 2.5% formic acid, protein samples were exposed to microwave irradiation. LC-MS/MS analysis of the resulted peptide mixtures indicated that oxygen in the carboxyl groups from glutamic acid, aspartic acid, and the C-terminal residues could be efficiently exchanged with O-18 within less than 1.5 min. The rate of back exchange was so slow that no detectable back exchange could be found during the HPLC run.