on 08-24-201204:42 AM - edited on 10-15-202111:09 AM by Closed Account
Hsiao HH, Urlaub H. Proteomics. 2010 Nov;10(21):3916-21. We describe a novel method, termed "pseudo-neutral-loss scan" MS, for selectively probing phosphopeptides and glycopeptides on a LTQ-Orbitrap mass spectrometer. The instrument has been programmed such that an in-source CID energy is applied to all species that eluted from LC column and were subsequently ionised in the electrospray ion source. Ion pairs that differ in the mass of a neutral loss of phosphoric acid or monosaccharide residues are automatically selected for CID MS/MS and further for multi-stage-activation MS3. Our method should prove useful for a highly selective and sensitive approach to identify phosphopeptides and glycopeptides from purified protein digestion without any further enrichment, and could potentially be of use in more complex mixture.