Galactose-terminated oligosaccharides

Scheme 4.21 Synthesis of galactose-terminated oligosaccharides catalysed hy two enzymes.

Incomplete (N-linked) glycosylation prompts decreased in vivo activity due to more rapid hepatic clearance of the EPO molecule. Enzymatic removal of terminal sialic acid sugar residues from oligosaccharides exposes otherwise hidden galactose residues. These residues are then free to bind specific hepatic lectins, which promote EPO removal from the plasma. The reported plasma tm value for native EPO is 4-6 h. The tm for desialated EPO is 2 min. Comparison of native human EPO with its recombinant form produced in CHO cells reveals very similar glycosylation patterns. 

One of the applications of CE for carbohydrate analysis that has shown increase acceptance in the biotechnology industry is the relative distribution of the N-linked oligossacharides on the conserved asparagines residue on the Fc portion of rMAbs. The advantages of CE over traditional methods include enhanced separation efficiencies, shorter analysis time, and improved robustness. The oligosaccharides present on a monoclonal antibody are asialo-N-linked complex biantennary structures with a core fucose, typical of the structures produced in the Chinese hamster ovary (CHO) cells. The main forms share the fucosylated branched core structure but vary in their terminal galactose occupancy ... 

Oral mucosae are covered with mucus which serves as a link between the adhesive and the membrane. Mucus is a glycoprotein consisting of a large peptide backbone with pendant oligosaccharide side chains. The side chains terminate in sialic or sulfonic acids, L-fucose, sulfated galactose, or A -acetylglucosamine. The glycoprotein component imparts the viscous or gel-like (non-Newtonian) nature due to its capacity... 

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