Isolation of acidic glycopeptides from urine by means of anion-exchange resins. Application to some cases of glycosphingolipidosis or mucolipidosis

Abstract

An acidic fraction containing aminosugar was isolated by means of Dowex 1 from normal human urine which had previously been filtered through Ecteolacellulose. After purification, the fraction was shown to be composed of peptides and carbohydrates in comparable amounts. Threonine, serine and dicarboxylic acids were the principal amino acids. The carbohydrate moiety was mainly composed of galactose and glucosamine in the approximate ratio 3 : 1, together with smaller amounts of fucose, sialic acid, galactosamine and mannose. The presence of an O-glycosidic bond to threonine was shown by alkali treatment in reducing conditions. The fraction is probably a mixture of acidic glycopeptides. Fractions showing similar characteristics were isolated from urine of patients with Niemann-Pick disease, Gaucher's disease, I-cell disease, Ehlers-Danlos syndrome. Slight differences from the normal were found in the composition of the fraction isolated from GM1-gangliosidosis type 1.