Search algorithm for determining differences in the MS/MS spectra of aspartate isomers in amyloid-bata peptides

摘要

An algorithm for qualitatively distinguishing peptides with post-translational modifications which are not accompanied by a change in the molecular weight of the molecule is proposed and demonstrated on the MS/MS fragmentation spectra of amyloid-beta fragment 1-16 carrying normal and iso-Asp7 residue obtained using different fragmentation methods such as CID, ECD and ETD. A number of differences in the fragmentation spectra of these peptides was detected, like the b6+H2O ion in the CID spectra and the c6+57 and z10-57 ions for the ECD and ETD spectra, what is in good agreement with earlier published data.