The invention provides a process for analysis of terminal sections of proteins comprising the steps of- providing one original isolated protein or a mixture of at least 2 original proteins,- digesting the original protein or mixture of original proteins by one exopeptidase, which is a carboxypeptidase or an aminopeptidase, to generate terminal peptide sections of the isolated protein or of the mixture of proteins, and free amino acids,- separating the terminal peptide sections from the free amino acids,- determining the masses, and preferably additionally determining fragmentation spectra, of the terminal peptide sections by mass spectrometry, preferably by ESI-MS/MS, and- comparing the determined masses, and preferably comparing the fragmentation spectra, to pre-determined masses of peptides to identify the amino acid sequences of the terminal peptide sections,- from the determined masses identifying terminal peptide sections- and assigning the terminal peptide sections having the same sequence of terminal amino acids to an individual group, and for the individual group classifying the terminal peptide sequences as belonging to one individual terminus of an original protein each.
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