Oligosaccharides reductive amination

Because reduction of the oligosaccharide occurs in the reductive-amination reaction, affinity adsorbents prepared by this route contain one glycosyl residue fewer than the original oligosaccharide. Adsorbents having such ligands may have low utility. The structure of the product obtained from lactose and 2-aminoethylpoly(acrylamide) by the reductive-amination route is shown in 6. 

Mishnick and co-workers have developed several techniques for determining the positions of substitutions on monosaccharide units and distribution of substituents along deriva-tized polysaccharide chains, primarily cellulose derivatives. Examples are found in references [61,62,63,64,65,66,67,68,69,70]. An important method involves perdeuteromethylation followed by partial acid-catalyzed hydrolysis, then reductive amination with propylamine, and finally permethylation to yield completely O- and A-alkylated charged oligosaccharides that are analyzed by MALDI-TOF-MS [68,70]. Statistical methods are then applied. 

Sulfated heparin oligosaccharides were coupled to aromatic spacers by reductive amination to investigate their binding to platelets [272,273]. 

Suzuki et al. [57] systematically compared the responses of some oligosaccharides derivatized with PA, ABEE, PMP, 4-methoxyphenyl-3-methyl-5-pyrazolone, 2-aminoethanethiol, and 2-aminobenzenethiol in continuous-infusion ESl-MS and frit-FAB-MS. In ESl-MS, the PMP derivatives gave the best results. Reductively aminated oligosaccharides can be analysed as [M+H]" or [M+Na]" in positive-ion ESl-MS and as [M-H] in negative-ion ESl-MS. 

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