Mass spectrometric sequencing (MS/MS) of the phosphopeptide-containing Y359.

The radioactive fraction containing the 2⁺ ion m/z 843 isolated by immobilized metal affinity chromatography and reverse-phase chromatography was subjected to sequence analysis by collisionally activated dissociation using a triple quadrupole mass spectrometer. The resultant MS/MS spectrum is shown with the sequence ions labeled as indicated.