Isolation of phosphopeptides by p/-difference-based electrophoresis

Yingda Xu, Robert Sprung, Won Kwon Sung, Chan Kim Sung, Yingming Zhao

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Effective proteomics studies of protein phosphorylation require an efficient enrichment method for phosphopeptides, which remains a challenge. Here, we describe the discovery of p/differences between methylated phosphopeptides (typically <7.4) and methylated nonphosphorylated peptides (typically >9.0). This p/ difference allows isolation of methylated phosphopeptides from the methylated nonphosphopeptides by in-solution isoelectric focusing. We proved the principle of such a novel approach by isolating a phosphorylated peptide from nonphosphorylated tryptic digest of myoglobin. While the principle for p/-based, in-solution electrophoresis is proven, it requires further development for practical application. The method described here provides a stepping stone toward more reliable, convenient method for efficient isolation of phosphopeptides.

Original languageEnglish (US)
Pages (from-to)1153-1157
Number of pages5
JournalJournal of Proteome Research
Issue number3
StatePublished - Mar 1 2007


  • IMAC
  • Isoelectric focusing
  • Phosphopeptides
  • Sample enrichment
  • p/

ASJC Scopus subject areas

  • Biochemistry
  • Chemistry(all)


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