Fig. 2.

MS2 spectra for the most abundant N-glycan at N45, N162 and N169. A, N45 glycopeptide (from NK13). B, N162 glycopeptide (from NK08). A cysteine residue modified by iodoacetamide is indicated with a red “IAM.” C, N169 glycopeptide (from NK13). Inserts indicate the parent ion and charge as well as the observed and expected mass. Identification was based on mass of the parent ion, mass of fragmented ions and characteristic oligosaccharide oxonium ions. See also Table II and supplemental Fig. S4.