Figure 1.

A representative example of the analysis for fractionated serum protein digest by liquid chromatography with tandem mass spectrometry (LC-MS/MS). (a) Base peak chromatogram based on total ion chromatography, the peptides indicate identified peptides of SPA3N. (b) The sequence of SPA3N, the peptides in the red boxes indicate peptides found by MS/MS. (c) The experimental MS/MS spectrum for the SPA3N doubly charged tryptic peptide sequence AKALYQAEAFTADFQQSR among the identified peptides by matching a peptide fragmentation pattern.