Fragmentation of phosphopeptides by atmospheric pressure MALDI and ESI/ion trap mass spectrometry

Susanne C. Moyer, Robert J. Cotter, Amina S. Woods

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


An investigation of phosphate loss from phosphopeptide ions was conducted, using both atmospheric pressure matrix-assisted laser desorption/ionization (AP MALDI) and electrospray ionization (ESI) coupled to an ion trap mass spectrometer (ITMS). These experiments were carried out on a number of phosphorylated peptides in order to investigate gas phase dephosphorylation patterns associated with phosphoserine, phosphothreonine, and phosphotyrosine residues. In particular, we explored the fragmentation patterns of phosphotyrosine containing peptides, which experience a loss of 98 Da under collision induced dissociation (CID) conditions in the ITMS. The loss of 98 Da is unexpected for phosphotyrosine, given the structure of its side chain. The fragmentation of phosphoserine and phosphothreonine containing peptides was also investigated. While phosphoserine and phosphothreonine residues undergo a loss of 98 Da under CID conditions regardless of peptide amino acid composition, phosphate loss from phosphotyrosine residues seems to be dependent on the presence of arginine or lysine residues in the peptide sequence.

Original languageEnglish (US)
Pages (from-to)274-283
Number of pages10
JournalJournal of the American Society for Mass Spectrometry
Issue number3
StatePublished - 2002
Externally publishedYes

ASJC Scopus subject areas

  • Structural Biology
  • Spectroscopy


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