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. Author manuscript; available in PMC: 2012 Dec 6.
Published in final edited form as: Nat Protoc. 2011 Oct 13;6(11):1695–1709. doi: 10.1038/nprot.2011.388

Figure 3.

Figure 3

Protein identification workflow. Representative workflow for protein identification by MS/MS. (a) Tissue section is microspotted with trypsin and matrix for MALDI MS/MS analysis. (b) The mass spectrum produced is acquired, and a parent ion of m/z 1,460.9 is selected for fragmentation. (c) Magnification of the parent ion peak at m/z 1,460.9 shown in panel b. The peak at m/z 1,460.9 is the monoisotopic peak for the intact protonated peptide. The three peaks at higher mass, each separated by 1 Da, result from incorporation of one or more of the less abundant isotopes into the molecule, with 13C at a natural abundance of 1.11% being the main contributor. (d) MS/MS spectrum of the 1,460.9 parent ion and analysis of the fragment ions produced. This figure is reproduced, with permission, from reference 6.