Peptide and Protein Quantitation by Acid-Catalyzed <sup>18</sup>O-Labeling of Carboxyl Groups
作者:Erik Haaf、Andreas Schlosser
DOI:10.1021/ac202561m
日期:2012.1.3
We have developed a new method that applies acidic catalysis with hydrochloric acid for 18O-labeling of peptides at their carboxyl groups. With this method, peptides get labeled at their C-terminus, at Asp and Glu residues, and at carboxymethylated cysteine residues. Oxygen atoms at phosphate groups of phosphopeptide are not exchanged. Our elaborated labeling protocol is easy to perform, fast (5 h and 30 min), and results in 95–97 atom % incorporation of 18O at carboxyl groups. Undesired side reactions, such as deamidation or peptide hydrolysis, occur only at a very low level under the conditions applied. In addition, data analysis can be performed automatically using common software tools, such as Mascot Distiller. We have demonstrated the capability of this method for the quantitation of peptides as well as for phosphopeptides.
我们开发了一种新方法,利用盐酸的酸性催化作用对肽的羧基进行 18O 标记。利用这种方法,肽的 C 端、Asp 和 Glu 残基以及羧甲基半胱氨酸残基都会被标记。磷酸肽磷酸基上的氧原子不会发生交换。我们精心设计的标记方案操作简便、速度快(5 小时 30 分钟),可使羧基上的 18O 含量达到 95-97 原子%。在应用条件下,脱酰胺或肽水解等不希望发生的副反应发生率极低。此外,数据分析还可通过 Mascot Distiller 等常用软件工具自动完成。我们已经证明了这种方法对肽和磷酸肽的定量能力。