title: N-acetylgalactosamine-6-sulfate sulfatase in man. Absence of the enzyme in Morquio disease.
abstract: Human N-acetylgalactosamine-6-sulfate sulfatase (6-sulfatase) activity is measured by using as a substrate a sulfated tetrasaccharide obtained by digesting purified chondroitin-6-sulfate (C-6-S) with testicular hyaluronidase. The amount of inorganic sulfate released is measured turbidimetrically. The enzyme from human kidney has a pH optimum of 4.8; its activity is augmented by low levels of NaCl and inhibited by phosphate and high levels of NaCl. Free glucuronate, acetylgalactosamine, inorganic sulfate, polymeric C-6-S, or tetrasaccharide obtained from chondroitin-4-sulfate do not affect the enzyme activity. The method may be used for the diagnosis of Morquio disease since extracts of Morquio fibroblasts are devoid of 6-sulfatase activity.
mesh_terms: D002809:Chondroitin Sulfates / Q000032:analysis; D002810:Chondroitinases and Chondroitin Lyases / Q000032:analysis*; D002811:Chondroitinsulfatases / Q000032:analysis*; D004796:Clinical Enzyme Tests / Q000379:methods*; D006595:Hexosamines / Q000032:analysis; D006603:Hexuronic Acids / Q000032:analysis; D006801:Humans; D007668:Kidney / Q000201:enzymology; D009085:Mucopolysaccharidosis IV / Q000175:diagnosis*; D013431:Sulfates / Q000032:analysis
chemical_list: D006595:Hexosamines; D006603:Hexuronic Acids; D013431:Sulfates; D002809:Chondroitin Sulfates; D002811:Chondroitinsulfatases; D002810:Chondroitinases and Chondroitin Lyases