Sequence-ion Studies in Peptides: the Generation of C''Ions - Part 2

Article abstract of DOI:10.1002/oms.1210281014

The mechanism for the formation of C''_x-type ions in which x (+) ions of two model peptides (VGSE and AAA) with those of their corresponding d + D>(+) ions, in which all exchangeable hydrogens are replaced with deuterium, revealed that in the case of VGSE the hydrogen atom from the hydroxyl group in the serine residue and/or from the amide group of the adjacent amino acid must be involved in the migration process which leads to the formation of C''₂-type ions.The second peptide (AAA) shows the exclusive transfer of the amide hydrogen atom in the formation of the C''₁ ion.The mechanism differs from an earlier reported reaction channel which appeared to be applicable to the formation of C''_n-1-type ions.The most plausible neutral species which is eliminated in the formation process of the C''_x ion from (+) is proposed on the basis of relative stability calculations.