Identification of phosphorylation sites in peptides using a gas-phase sequencer

Yuhuan Wang, Carol J. Fiol, Anna A. DePaoli-Roach, Alexander W. Bell, Mark A. Hermodson, Peter J. Roach

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


A simple procedure is described for determining the location of phosphorylation sites in phosphopeptides. The method employs measurement of 32P-labeled inorganic phosphate release during Edman degradation cycles using a gas-phase sequencer. The procedure is based on extracting peptides and inorganic phosphate from portions of the sample filter at strategic cycles in the sequence analysis followed by determination of the relative amounts of phosphate and phosphopeptide. One advantage of this technique is the very high recovery of the phosphate associated with the peptide, 80-97% in this study. In the course of this work, it was also found that phosphoserine residues themselves caused reduced efficiency of the Edman degradation as compared with unesterified serine residues. The present procedure has the merit of being simple and easy to apply.

Original languageEnglish (US)
Pages (from-to)537-547
Number of pages11
JournalAnalytical biochemistry
Issue number2
StatePublished - Nov 1 1988


  • phosphorylation sites
  • phosphoserine
  • protein sequencing

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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