Efficient and Selective Chemical Labeling of Electrochemically Generated Peptides Based on Spirolactone Chemistry

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• 作者：Tao Zhang ; Xiaoyu Niu ; Tao Yuan ; Marco Tessari ; Marcel P. de Vries ; Hjalmar P. Permentier ; Rainer Bischoff
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：June 21, 2016
• 年：2016
• 卷：88
• 期：12
• 页码：6465-6471
• 全文大小：421K
• 年卷期：0
• ISSN：1520-6882

文摘

Specific digestion of proteins is an essential step for mass spectrometry-based proteomics, and the chemical labeling of the resulting peptides is often used for peptide enrichment or the introduction of desirable tags. Cleavage of the peptide bond following electrochemical oxidation of Tyr or Trp results in a spirolactone moiety at the newly formed C-terminus offering a handle for chemical labeling. In this work, we developed a highly efficient and selective chemical labeling approach based on spirolactone chemistry. Electrochemically generated peptide-spirolactones readily undergo an intramolecular rearrangement yielding isomeric diketopiperazines precluding further chemical labeling. A strategy was established to prevent intramolecular arrangement by acetylating the N-terminal amino group prior to electrochemical oxidation and cleavage allowing the complete and selective chemical labeling of the tripeptide LWL and the decapeptide ACTH 1-10 with amine-containing reagents. As examples, we show the successful introduction of a fluorescent label and biotin for detection or affinity enrichment. Electrochemical digestion of peptides and proteins followed by efficient chemical labeling constitutes a new, powerful tool in protein chemistry and protein analysis.