Patent ID: 7588944

Claim:
A method of analyzing the C-terminal amino acid sequence of a peptide, comprising: obtaining C-terminal-deleted peptides lacking amino acid residues from said C-terminal by degrading the amino acids from said peptide C-terminal sequentially; measuring the molecular weight of said C-terminal-deleted peptides; and determining the decrease in molecular weight associated with said sequential degradation from the difference between the molecular weight obtained in said measuring the molecular weight of the C-terminal-deleted peptides and the molecular weight of said peptide, and analyzing said C-terminal amino acid sequence based on the decrease in said molecular weight, wherein said C-terminal amino acids are degraded by making said peptide substantially bring into contact with an alkanoic anhydride in said obtaining C-terminal-deleted peptides, wherein said obtaining the C-terminal-deleted peptides is carried out in a system containing a basic nitrogen-containing aromatic ring compound, and wherein said C-terminal amino acids are degraded with alkanoic anhydride, without a perfluoroalkanoic acid or the anhydride thereof, in said step of obtaining C-terminal-deleted peptides.