Fig. 2.

Linear ion trap CID spectrum of the same glycopeptide AVGAQVLESTPPPHVMR modified with SAGalGalNAc as in Fig. 1. Precursor ion was at m/z 815.7307(3+). The abundant peptide fragments in the spectrum were formed by cleavage N-terminal to the first Pro residue. The glycosylated half of the structure (b ₁₀) can be observed with the sugar attached as well as partially or completely deglycosylated—the number of asterisks indicates the number of carbohydrate units lost