Figure 1

Schematic diagram of the serum protein-derived biantennary N-linked glycan structures that were analyzed by MS. Eight main biantennary serum glycoprotein-derived N-glycan structures were identified. These comprised six neutral and two acidic (sialylated) glycans. The glycans are designated as G0, G1 and G2, according to the number of terminal galactose residues, and monosialylated and or A2, according to the number of terminal sialic acid residues that decorate the core pentasaccharide (GlcNAc2, Man3). Three of the glycans are F; giving rise to G0F, G1F and G2F structures. Monosialylation and monogalactosylation may occur on either the α1–3 or α 1–6 arm of the biantennary structures.