Application of carboxypeptidase Y and fast atom bombardment mass spectrometry for C-terminal sequencing of small peptides.

The application of fast atom bombardment (FAB) mass spectrometry to the C-terminal amino acid sequence determination of peptides is reported. FAB mass spectrometric analysis of the peptides formed by carboxypeptidase Y (CPY) digestion conveniently provides information about C-terminal amino acid sequences. In these experiments, we accomplished the determination of C-terminal region amino acid sequence of Bradykinin and Angiotensin II. We describe advantages of the combination experiment of CPY and FAB mass spectrometry for C-terminal region amino acid studies of small peptides. The significant advantages of this method are the ability to study peptides without derivatization and the elimination of the separation step of liberated C-terminal amino acids and peptides. With this method, we could overcome several problems which conventionally happened in C-terminal sequence analysis.