Mannose hexamers

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-... 

Fig. 3-121. Separation of mannose hexamers from pathological urine. - Separator column IonPac AS6A eluent 0.1 mol/L NaOH + 0.027 mol/L NaOAc flow rate 0.8 mL/min detection and injection volume see Fig. 3-105 solute concentration 50 ppm.

A number of carbohydrate recognition domains (CRDs) of animal lectins are known to exist as clusters. ASGP-Rs exist as bundle of hexamers, mannose 6-phosphate receptor and galectin-3 are known as dimers, while mannose binding proteins and receptors form multiple CRDs [31]. 

These enzymes vary widely in secondary and tertiary structure.1273 Mannose-6-phosphate isomerase is a 45 kDa Zn2+-containing monomer. The larger 65 kDa L-fucose isomerase, which also acts on D-arabinose, is a hexameric Mn2+-dependent enzyme.1273 L-Arabinose isomerase of E. coli, which interconverts arabinose and L-ribulose, is a hexamer of 60-kDa subunits128 while the D-xylose isomerase of Streptomyces is a tetramer of 43-kDa subunits.129 The nonenzymatic counterpart of the isomerization catalyzed by the enzyme is the base-catalyzed Lobry deBruyn-Alberda van Ekenstein transformation (Eq. 13-25).130... 

Enzymic fucosylation of an -acetyllactosamine-derived hexamer afforded two branched heptasaccharides and a difucosylated product. Substitutions occurred at 0-3 of the two glucosamine units other than that at the reducing end. A heptasaccharide anchor compound based on the inositol pentamer compound noted in reference 146, and carrying a GalNAc unit p-(l->4)-linked on the central mannose moiety and a further a-(l- 2)-linked D-mannose unit on the non-reducing terminal mannose molecule, has been synthesized in a phosphory-lated form. ... 

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