The Structure of a New Sialic Acid-Containing Decasaccharide from the Urine of a Patient with Mucolipidosis

Abstract

A new sialic acid-containing oligosaccharide was isolated from urine of a patient with a type of mucolipidosis newly recognized by Orii et al. (1972). This compound was composed of galactose (2 mol), mannose (3 mol), N-acetylglucosamine (3 mol) and sialic acid (2 mol). On the basis of sequential glycosidase digestion, methylation analysis and the Smith degradation, the structure of this oligosaccharide was elucidated as follows: NeuAc.alpha.2-6Gal.beta.1-4GlcNAc.beta.1-2Man.alpha.1-3[NeuAc.alpha.2-6Gal.beta.1-4GlcNAc.beta.1-2Man.alpha.1-6]Man.beta.1-4GlcNAc. The increased excretion of this oligosaccharide may be caused by the impaired metabolism of glycoproteins having N-glycosidic linkage.