Urinary glycopeptides of fucosidosis.

Fucosidosis is unique among congenital exoglycosidase deficiencies, because not only oligosaccharides but large amount of glycopeptides are excreted in the urine. The structures of 22 major glycopeptides isolated from urine of a fucosidosis patient were determined. One of the prominent features common to all these glycopeptides was that they all contain 1 fucosyl residue at either C-3 or C-6 position of the N-acetylglucosamine which is linked to asparagine. Possibly, accumulation of glycopeptides in fucosidosis urine is caused by the inability of human endo-beta-N-acetylglucosaminidase to cleave the asparagine-linked sugar chains, which have a fucose at the innermost N-acetylglucosamine residue.