Peptide Mapping/Complete Protein Characterization

Non-de novo approach, analyzing peptides of a protein of a highly pure source (including basic modifications). Multiple proteases to provide overlapping sequence information as well as alignment are often necessary. Intact analysis of the pure proteoform(s) is also complementary. 

In order to characterize the complete primary structure of a protein molecule, from N- to C-terminal, we digest the intact protein into smaller polypeptides. Each protease presents a unique map of polypeptides where each peptide provides sequence information, retention time and intensity and is fully characterized. Different proteases provide different maps; after the contents of the map are fully characterized, differences therein can be readily described.