Microwave-assisted 18O-labeling of proteins catalyzed by formic acid

Ning Liu*, Hanzhi Wu, Hongxia Liu, Guonan Chen, Zongwei CAI

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

14 Citations (Scopus)


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 18O-labeling method utilizing microwave-assisted acid hydrolysis was developed. After being dissolved in 16O/18O (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 18O within less than 15 min. The rate of back exchange was so slow that no detectable back exchange could be found during the HPLC run.

Original languageEnglish
Pages (from-to)9122-9126
Number of pages5
JournalAnalytical Chemistry
Issue number21
Publication statusPublished - 1 Nov 2010

Scopus Subject Areas

  • Analytical Chemistry


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