Structure of the accumulating oligosaccharide in fucosidosis.

Abstract

Two water-soluble complex carbohydrate storage products were isolated from tissues and urine of patients with an inherited deficiency of lysosomal a-t-fucosidase (fucosidosis).The major component was an oligosaccharide of approximate molecular weight 1700, indicating that it was a dekasaccharide.From a combination of sequential digestion with purified exo-glycosidases, periodate oxidation and permethylation in conjunction with gas-liquid chromatographic mass spectrometric analysis, the structure was found to be: Fuc(al-B)Gal-(pl-4) GlcNAc (PI-2)Man Fuc(ul~2) Gal (Pl-4) GlcNAc(pl-2) Man] (al-3/6) Man (@l-4) GlcNAc, although there was some evidence for heterogeneity at the mannose branchpoint.This material is structurally related to the stored oligosaccharides in patients with inherited deficiencies of fi-galactosidase (G M,-gangliosidosis) and N-acetyl-P-hexosaminidase (G M,-gangliosidosis).A disaccharide with the probable structure Fuc(cul-6)GlcNAc was found in lesser amounts in tissues; both are believed to be derived from the impaired catabolism of large numbers of different glycoproteins.