Sanfilippo D syndrome: estimation of N-acetylglucosamine-6-sulfatase activity with a radiolabeled monosulfated disaccharide substrate.

Abstract

N-Acetylglucosamine-6-sulfatase activity was assayed by incubation of the radiolabeled disaccharide O-(a-N-acetylglucosamine-6-sulfate)-(1----3)-L-[6-3H]-idonic acid (GlcNAc6S-IdOA), with homogenates of leucocytes, cultured fibroblasts, and urine from normal individuals, patients affected with N-acetylglucosamine-6-sulfatase-deficiency (Sanfilippo D syndrome, mucopolysaccharidosis type IIID), and patients affected with other mucopolysaccharidoses and lysosomal storage disorders. The assay clearly distinguished affected homozygotes from their obligate heterozygotes and normal controls and other lysosomal storage disorders. Sulfatase activity in fibroblasts, leucocytes, and urine toward GlcNAc6S-IdOA exhibited a pH optimum at 4.2, 4.5, and 5.1, respectively. Sulfatase activity in fibroblasts had an apparent Km of 7.2 microM and was significantly inhibited by both sulfate and phosphate ions. The action of fibroblast or leucocyte N-acetylglucosamine-6-sulfatase activity toward GlcNAc6S-IdOA is recommended for the routine enzymatic detection and classification of mucopolysaccharidosis type IIID patients.

• Authors: C Freeman, J J Hopwood
• Journal: Analytical biochemistry (Anal Biochem) Vol. 176 Issue 2 Pg. 244-8 (Feb 01 1989) ISSN: 0003-2697 [Print] United States
• PMID: 2500866 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Disaccharides
• Tritium
• O-((Nalpha)-acetylglucosamine 6-sulfate)-(1-3)-idonic acid
• Sulfatases
• N-acetylglucosamine-6-sulfatase

Topics

• Amnion (enzymology)
• Chorionic Villi (enzymology)
• Disaccharides
• Fibroblasts (enzymology)
• Humans
• Leukocytes (enzymology)
• Mucopolysaccharidoses (diagnosis)
• Mucopolysaccharidosis III (diagnosis)
• Skin (enzymology)
• Substrate Specificity
• Sulfatases (analysis)
• Tritium