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Enhanced detection and identification of multiply phosphorylated peptides using TiO 2 enrichment in combination with MALDI TOF/TOF MS
Author(s) -
Schmidt Andreas,
Csaszar Edina,
Ammerer Gustav,
Mechtler Karl
Publication year - 2008
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200800279
Subject(s) - chemistry , electron transfer dissociation , mass spectrometry , phosphorylation , peptide , chromatography , dissociation (chemistry) , protein phosphorylation , tandem mass spectrometry , biochemistry , protein kinase a
The analysis of PTMs such as phosphorylation has become an important field in MS because they can directly indicate protein states and interactions. Whereas the characterization of singly and doubly phosphorylated peptides has almost become routine, identifying phosphorylation events at multiple residues within a small region of a protein is still problematic. The identification of multiple modifications can be further hampered by low sequence information due to multiple neutral losses from phosphorylated side chains. Here we present a strategy for the analysis of complex phosphopeptides that combines peptide enrichment by titanium dioxide, separation by RP separation on monolithic columns and MS using high energy HE‐CAD in a MALDI TOF/TOF analyser. Using synthetic phosphopeptides our approach is compared to multistage activation (MSA) MS/MS and the recently described electron transfer dissociation (ETD) method using an ESI‐LTQ mass spectrometer.