| Abstract: | Fragmentations of N-benzyloxycarbonyl-protected tripeptide ethyl esters, in which changes in the numbers and positions of prolyl residues were observed, were examined by negative-ion fast atom bombardment mass spectrometry. A significant difference was found among the intensities of the fragment ions formed by cleavage of the benzyloxycarbonyl group, depending on the numbers and positions of prolyl residues in the derivatives. These results suggest that the fragmentations of the peptide derivatives in negative-ion fast atom bombardment mass spectrometry depend on the conformational differences in the peptide derivatives due to the existence of proline, and permit the prediction of the positions of proline in the peptides. |
