Oligosaccharides, branching

Camilleri, P., Harland, G. B., and Okafo, G., High resolution and rapid analysis of branched oligosaccharides by capillary electrophoresis, Anal. Biochem., 230, 115,1995. 

Takahashi and coworkers described the one-pot synthesis of core 2 branched oligosaccharides [236], It was found that boron trifluoride complexed with a tri-methylsilyl ether would enhance the nucleophilidty of the silyl ether. As a result, glycosylations of the 6-O-TMS modified acceptor with a glycosyl fluoride provided... 

Fig. 3—Possible solution conformers of oligosaccharide sequences related to the Le and Leb antigens (Lea,Lex, sialyl Le", sialyl Lex, ALeb, ALey). As described in the text, oligosaccharides in solution sample 3D space in local energy-minima wells, so that the conformations shown are approximate only. The models stand only to show the stereochemical hindrance to movement in these branched oligosaccharides. The molecules are shown without the anomeric hydroxyl group. 

With this solid-phase methodology in hand, the synthesis of branched oligosaccharides could be investigated. This led to the preparation of pentasaccharide 15 related to /V-glycan chains (Scheme 4.5).3... 

Gangliosides branched oligosaccharide chains terminating in the 9-carbon sugar, sialic acid (N-acetylneuraminic acid, NANA)... 

Beta-1-6 branched oligosaccharides as a marker of tumor progression in human breast and colon neoplasia. 

Monosaccharides can be assembled into an almost limitless variety of oligosaccharides, which differ in the stereochemistry and position of glycosidic bonds, the type and orientation of substituent groups, and the number and type of branches. Oligosaccharides are far more information-dense than nucleic acids or proteins. 

The branched oligosaccharides of glycoprotein surfaces are formed on asparagine side chains of selected cell surface proteins. The oligosaccharide at the left is formed in the ER and is transferred intact (Fig. 20-6) to an acceptor asparagine. 

N. E. Nifantiev, A. S. Shashkov, G. M. Lipkind, and N. K. Kochetkov, Synthesis, NMR, and conformational studies of branched oligosaccharides. 7. Synthesis and l3C NMR spectra of 2,3-di-O-glycosyl derivatives of methyl a-L-rhamnopyranoside and methyl a-D-mannopyrano-side, Carbohydr. Res., 237 (1992)95-113. 

B. Spengler, D. Kirsch, R. Kaufmann, and J. Lemoine, Structure analysis of branched oligosaccharides using post-source decay in matrix-assisted laser desorption ionization mass spectrometry, Org. Mass Spectrom., 29 (1994) 782-787. 

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