Practice question

Peptide backbone contains three bonds repeating per residue: N-Cα, Cα-C carbonyl, and C-N amide peptide bond. Fragmentation nomenclature associates specific bond cleavage with ion type. Breaking the amide linkage CO-NH retains N-terminal portion as b ion and C-terminal portion as y ion, most common pathway under collision-induced dissociation due to relative bond weakness and proton mobility mechanism. Cleavage of N-Cα produces c/z ions characteristic of electron transfer dissociation, while Cα-CO yields a/x ions. Thus CO-NH scission directly generates b/y series used for sequence determination in proteomics data analysis routinely performed.