Fig. 2

A schematic of MSMS spectra of a protonated short-chain peptide, -Gly-Leu-. These MSMS spectra were acquired on an Orbitrap instrument using collision energy of NCE 10%, showing fragmentation including neutral losses (in blue) and amino acid residue (in green). In this example, as for a dipeptide, only one peptide bond was broken, i.e., the most intense ion in the spectra, 132 m/z, loss of 57 from the molecular ion [M]⁺ gives a glycine. This peptide was identified in wheat hydrolysate (A) and as compared to a synthetic peptide (B), both spectra are identical