Sequencing of peptide-derived Amadori products by the electron capture dissociation method.

The electron capture dissociation (ECD) of peptide-derived Amadori products has been successfully applied for their sequencing. In contrast to the collision induced dissociation (CID), based on the vibrational excitation of peptides, the ECD method does not produce ions formed by fragmentation of the hexose moiety, that facilitates interpretation of the obtained spectra. The fragmentation spectrum is dominated by c(n) and z.(n) ions, providing the sufficient information for sequencing of peptides and establishing the location of glycated Lys residues in the peptide chain. The ECD experiments were conducted on a series of synthetic peptides and unseparated digests of glycated ubiquitin.