Fractionation and characterization of urinary heparan sulfate excreted by patients with Sanfilippo syndrome.

Urinary heparan sulfates (HS) from two siblings with mucopolysaccharidosis (MPS) III-B were fractionated by chromatography with Dowex 1 and Sephadex G-50. Their Mr ranged from 1600 to 8000, and 95% of them were included in the region less than 5000. Fractions with lower Mr contained larger amounts of O-and N-sulfates. The chemical analysis and deaminative cleavage of HS suggested that an intact HS molecule was composed of some blocks rich in GlcNAc and GlcUA and other blocks rich in GlcNS, IdUA and O-sulfate. GlcNAc-UA-GlcNS-UA-GlcNAc-UA-GlcNAc was found to be a major oligosaccharide of HS with Mr less than 1800. Trisaccharides, GlcNAc-GlcUA-aMan and GlcNAc-IdUA-aMan, were released from the nonreducing end of HS-oligosaccharides by deaminative cleavage. They carried 0-3 moles of ester sulfate. GlcNAc-IdUA-aMan was more sulfated than the other. The release of significant amounts of nonsulfated trisaccharide conform to the enzyme defect in this disease. Urinary HS obtained from another patient with MPS III were examined by the same way. Although the patient was not examined enzymatically, the structure of urinary GAG suggested a defect of alpha-N-acetylglucosaminidase in the patient.