Ladder sequencing Edman degradation methods

Sequence information can also be obtained using Edman degradation to remove amino-terminal residues from a peptide, to produce a collection of peptides. MALDI-TOF can then be used to obtain the peptides masses, and the sequence determined by mass difference between consecutive peptides. This methodology is called protein ladder sequencing, and allows information to be obtained for up to 30 residues. This method is useful for the identification of posttranslational modifications, such as phosphorylated amino acid residues.24... 

Many structural biology and biochemistry studies rely on the precise identification of the N-/C-terminal sequence of a protein (e.g., signal peptide identification, determining the cleavage site and specificity of a novel protease, etc.). Digestion of proteins in arrays of carboxypeptidase Y at different concentrations with MALDl-MS-based readout can be employed to derive C-terminal sequence information for proteins. The amino-terminus of a protein can be derived by wet chemistries similar to Edman degradation coupled to MS-readout. This method of protein ladder sequencing, reported first by Kent and... 

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