Inhibition of protein carbamylation in urea solution using ammonium-containing buffers

Shisheng Sun, Jian Ying Zhou, Weiming Yang, Hui Zhang

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


Urea solution is one of the most commonly employed protein denaturants for protease digestion in proteomic studies. However, it has long been recognized that urea solution can cause carbamylation at the N termini of proteins/peptides and at the side chain amino groups of lysine and arginine residues. Protein/peptide carbamylation blocks protease digestion and affects protein identification and quantification in mass spectrometry analysis by blocking peptide amino groups from isotopic/isobaric labeling and changing peptide charge states, retention times, and masses. In addition, protein carbamylation during sample preparation makes it difficult to study in vivo protein carbamylation. In this study, we compared the peptide carbamylation in urea solutions of different buffers and found that ammonium-containing buffers were the most effective buffers to inhibit protein carbamylation in urea solution. The possible mechanism of carbamylation inhibition by ammonium-containing buffers is discussed, and a revised procedure for the protease digestion of proteins in urea and ammonium-containing buffers was developed to facilitate its application in proteomic research.

Original languageEnglish (US)
Pages (from-to)76-81
Number of pages6
JournalAnalytical biochemistry
Issue number1
StatePublished - Feb 1 2014


  • Ammonium-containing buffer
  • Carbamylation
  • Mass spectrometry
  • Proteomics
  • Urea

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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