Glycoprotein oligosaccharide side chains

Figure 2.10 Structure of two sample oligosaccharide side chains (one N-linked the other O-linked) found in glycoproteins. Man manose Gal galactose SA sailic acid GlcNAc W-acetyl glucosamine GalNAc W-acetyl galactosamine...

Antithrombin, already mentioned in the context of heparin, is the most abundantly occurring natural inhibitor of coagulation. It is a single-chain 432 amino acid glycoprotein displaying four oligosaccharide side chains and an approximate molecular mass of 58 kDa. It is present in plasma at concentrations of 150 pig ml 1 and is a potent inhibitor of thrombin (factor Ha), as well as of factors IXa and Xa. It inhibits thrombin by binding directly to it in a 1 1 stoichiometric complex. 

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... 

PAS staining (periodic acid - Schiff s reagent) colors compounds with vicinal hydroxyl groups, i.e., mainly oligosaccharide side chains in glycoproteins, glycolipids, and nucleic acids. The sensitivity and stability is much lower than the silver staining Protocol 2.4.2.S but more specific. 

Glycoproteins, such as horseradish peroxidase, are coupled selectively to other proteins or NH2-groups bearing molecules via oligosaccharide side chain oxidation. The vicinal OH groups of oligosaccharide residues are oxidized by periodate to aldehyde groups, which react with amines to form imines (Schiff bases). 

Other mutants of Chinese-hamster ovary-cells having decreased amounts of lipid-linked oligosaccharides are known, although they are less well characterized. G-Protein of vesicular stomatitis virus grown in one of these mutants appeared to contain fewer, but full-sized rather than truncated, oligosaccharide side-chains. There may be insufficient amounts of oligosaccharide precursor available for transfer to nascent glycoproteins.172... 

N-Acetylneuraminic acid N-Acetylneuraminic acid (NANA) is a member of the family of sialic acids, each of which is acylated at a different site. These compounds are usually found as terminal carbohydrate residues of oligosaccharide side chains of glycoproteins, glycolipids, or, less frequently, of glycosaminoglycans. The]... 

Some glycoproteins, particularly those with numerous, generally distributed, oligosaccharide side-chains, are able to form dispersions with stringy characteristics, as in nasal mucus or salivary discharges. The rheological implications of interactions between mucus and dmgs have been studied. As yet there is no coherent view as to what the ideal mucolytic... 

Another example of the high selectivity of a latexed anion exchanger for the analysis of structurally isomeric oligosaccharide side chains of a glycoprotein is the chromatogram in Fig. 3-121. It shows the separation of mannose hexamers with terminal N-... 

Presence of more than one type of oligosaccharide side chain in a particular glycoprotein ... 

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