XYLOSE-CONTAINING CARBOHYDRATE CHAINS DERIVED FROM N-GLYCOPROTEINS

Xylose-containing N-linked carbohydrate chains are integral parts of certain plant and animal glycoproteins. In all of the known structures, beta-D-xylose is 1-2-linked to beta-D-mannose of the trimannosyl-N,N'-diacetylchitobiose unit. If alpha-L-fucose is present at the asparagine-linked N-acetyl-D-glucosamine, then there are differences in the sites of its attachment, namely, alpha-1-3- or alpha-1-6-linked, depending on the biological origin. The alpha-D-mannose residues can be substituted with additional monosaccharides or 3-O-methylated. The state of the art with respect to structural analysis, organic synthesis, conformational analysis, biosynthesis, lectin binding, and immunological aspects is reviewed.