Figure 2.

Representative MS/MS spectra of permethylated N-linked glycans from the sera of patients with cholangiocarcinoma. Fragmentation of (A) parent ion at m/z=904²⁺ of high-mannose type structure and (B) parent ion at m/z=1276³⁺ of complex type structure are depicted. The parent ion at m/z=904²⁺ (structure 3) fragments in MS² to give m/z=765²⁺ (loss of reducing end GlcNAc; ∆m/z=139²⁺) and m/z=795²⁺ (loss of terminal man; ∆m/z=109²⁺). The parent ion at m/z=1276³⁺ (structure 9) fragments in MS² to give m/z=1105³⁺ and 1025³⁺ [loss of terminal NeuAc (first) and NeuAc (second) respectively; ∆m/z=125³⁺] and m/z=398 (terminal NeuAc with Na⁺). MS, mass spectrometry; m/z, mass/charge ratio; GlcNAc, N-acetylglucosamine; NeuAc, N-acetylneuraminic acid.