Mass Spectrometry: Peptide Sequencing


Electrospray and MALDI (matrix‐assisted laser desorption ionization) are two versions of desorption/ionization that allow modern mass spectrometry to be applied to the analysis of peptides and proteins. In addition to a direct indication of the molecular weight, the sequence of amino acids in a peptide can be deduced from the fragmentation pattern (the mass spectrum itself).

Keywords: electrospray; MALDI; signal suppression; mass spectrum; matrix‐assisted laser desorption ionization

Figure 1.

Conceptual respresentation of key bonds in a given peptide that break to form the indicated N‐terminal (a, b, c) or C‐terminal (x, y, z) fragments.

Figure 2.

ES‐CAD‐MS/MS mass spectrum of a peptide, LKRApTLG‐amide.

Figure 3.

ES‐CAD‐MS/MS mass spectrum of Ac‐TMPP derivative of LKRApTLG‐amide. The charged derivative (Ac‐TMPP) of the peptide promotes remote‐site fragmentation, which gives a more complete series of fragment ions (compared to that in Figure ) from which the sequence and locus of the phosphate group can be deduced.



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Further Reading

Watson JT (1997) Introduction to Mass Spectrometry, 3rd edn. Philadelphia: Lippincott‐Raven.

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Watson, J Throck(Apr 2001) Mass Spectrometry: Peptide Sequencing. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0003111]