ECD and IRMPD of Amyloid Beta Protein Fragment 1-40 and Synthetic Beta-linked Peptides.

摘要

Amyloid beta protein fragments 1-39 to 1-42 containing isomerized aspartic acid (Asp) (at 1, 7, and 23 residues) and deamidated glutamine at the N-terminus are known to accumulate in the brains of Alzheimer patients. Here we show development of methods to detect these modifications in Amyloid beta protein fragment 1-40 using electron capture dissociation. We also study small synthetic beta-linked peptides using IRMPD and/or ECD to distinguish beta_(2)-linked from (beta)_(3)-linked peptides, and study the fragmentation mechanism of these peptides since they contain an extra carbon in the peptide chain similar to the isoaspartic acid.