Low‐energy collision‐induced dissociation of protonated polyamino alcohol derivatives of peptides and N‐terminal blocked peptides

This investigation reports the low-energy collision-induced dissociation of the protonated molecules of polyamino alcohols, formed by chemical reduction of synthetic peptides and N-terminal blocked peptides, in order to evaluate its potential for peptide sequence determination. The CH2NH cleavage with charge retention on the Nterminus was prominent, and the entire sequence of ions produced in this manner was observed. Some of the sequence ions arising from CH2NH cleavage accompanied by migration of two hydrogens, and NHCαH cleavage with charge retention on the C-terminus, also occurred prominently. In addition, a great number of internal fragment ions were produced in relatively high abundance; these provided supplementary sequence information and were, in some cases, critical in determining the complete sequence. The usefulness of this method was exemplified by its application to the sequence determination of bacterial lipopeptides.