N-Acetyl-D-galactose

From the identification of these products it was possible to give a means of portraying the type of structure (LVIII) present in the carbohydrate molecule. In this, by glycosidic attachment, seven N-acetyl-D-glucosamine unitB and one D-galactose unit radiate from a central core of three D-mannose units. It is not yet clear by what linkages the d-mannose units are mutually attached, or to which D-mannose the d-galactose residue is linked. 

Keratan sulfate constitutes approximately half the total mucopolysaccharide fraction of bovine cornea, where it was isolated originally by Meyer et al. (M16). It occurs fairly widely in animal connective tissues, and its presence has been reported in nucleus pulposus (G2), aorta (B17), and costal cartilage (M20). Unlike the acid mucopolysaccharides described previously, keratan sulfate contains no uronic acid residue but is comprised of V-acetyl-n-glucosamine, D-galactose, and sulfate, in equimolar ratio. The small amount of L-fucose detected in acidic... 

Next, the sugar portion sensitive to oxidation was protected by means of acetylation, and the penta-O-acetyl-n-galactose diphenylformazan was oxidized with lead tetraacetate. By the action of the calculated amount of the oxidant, penta-O-acetyl-n-galactose diphenyltetrazolium chloride CG.T.C. acetate) was obtained as characteristically shaped, colorless prisms upon addition of an appropriate quantity of hydrochloric acid. Owing to its ionic structure, this compound is quite soluble in water and is readily reduced to the corresponding acetylated formazan, which is red. Saponification of the penta-O-acetyl-D-galactose diphenyltetrazolium... 

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