Metastable Atom-Activated Dissociation Mass Spectrometry (MAD-MS) of Phosphopeptide and Sulfopeptide Anions

摘要

We have demonstrated that MAD can effectively characterize phosphorylated and sulfonated peptides in negative or positive ion mode. We have shown that the presence of a modification does effect the way that dissociation occurs by altering the type and the amount of distinct fragment ions that are produced. Using the fragment ions produced, we were able to successfully identify and determine the location of the modifications on the peptide backbone. MAD is therefore a viable alternative to CID, ECD and ETD. MAD can achieve radical-like fragmentation of singly protonated precursor ions, which are inaccessible by ECD or ETD.