hymecromone and Leukodystrophy--Metachromatic

The properties of human tear 4-methylumbelliferone sulphate sulphatase (EC 3.1.6.1) have been investigated. More than 80% of the enzyme activity behaved as the acidic A isoenzyme on isoelectric focusing and DEAE-cellulose ion exchange chromatography. The distribution of enzyme activity in a normal population has been investigated. The least interindividual variation was seen when enzyme activities were calculated as units per mg tears. The alpha-galactosidase, beta-N-acetylglucosaminidase and sulphatase enzyme activities in human tears varied independently of each other. The use of tear sulphatases for the detection of metachromatic leukodystrophy (McKusick 24980) is discussed.

Topics: Acetylglucosaminidase; alpha-Galactosidase; Arylsulfatases; Humans; Hydrogen-Ion Concentration; Hymecromone; Leukodystrophy, Metachromatic; Sulfatases; Tears

A new technique is introduced for the differential assay of arylsulphatases A and B in centrifuged homogenates of cultured human skin fibroblasts, using 4-methylumbelliferyl-sulphate as a substrate and AgNO3 as a selective inhibitor of arylsulphatase A. The method can be applied in the diagnosis of metachromatic leucodystrophy, mucopolysaccharidosis type VI and mucosulphatidosis. Normal arylsulphatase activities were found in fibroblasts derived from patients with mucopolysaccharidoses types II, III-A and IV, known to be caused by deficiencies of various other sulphatases.

Topics: Cerebroside-Sulfatase; Chondro-4-Sulfatase; Diagnosis, Differential; Diploidy; Fibroblasts; Humans; Hymecromone; Leukodystrophy, Metachromatic; Mucopolysaccharidoses; Mucopolysaccharidosis VI; Silver Nitrate; Skin; Sulfatases

A sensitive fluorometric assay utilizing 4-methylumbelliferyl sulphate has been developed for the simultaneous determination of arylsulphatases A and B from leucocytes, based on the differential effect of silver ions on the two enzymes. The procedure allows discrimination between normal cases and those with metachromatic leucodystrophy.

Topics: Adolescent; Cerebroside-Sulfatase; Child; Child, Preschool; Chondro-4-Sulfatase; Humans; Hymecromone; Leukocytes; Leukodystrophy, Metachromatic; Methods; Middle Aged; Silver; Spectrometry, Fluorescence; Sulfatases

Two unrelated families with metachromatic leukodystrophy have been examined for the leukocyte enzyme arylsufatase A. The enzyme activities clearly reflect an autosomal recessive mode of inherence. All four parents showed heterozygote enzyme levels 40-60 percent of the control range while the two affected children had less than 20 percent normal activity. The two sibs of one affected child were shown to be heterozygote carriers. A simple screening method for sulfatase activity in tears has been developed which distinguished between metachromatic leukodystrophy patients and a control population which included other neurological disorders. Enzyme screening on tears may also be used to detect other lysosomal storage diseases including Tay-Sachs and Fabry disease.

Topics: Adult; Cerebroside-Sulfatase; Child; Child, Preschool; Clinical Enzyme Tests; Female; Heterozygote; Humans; Hymecromone; Leukocytes; Leukodystrophy, Metachromatic; Male; Sulfatases; Tears

Metachromatic leukodystrophy and Maroteaux-Lamy syndrome can be diagnosed by assay of leukocyte or fibroblast arylsulfatase A and B activity with the fluorogenic substrate 4-methylumbelliferyl sulfate. The arylsulfatases are extracted into a 27000 x g supernatant by sonication in 0.9% sodium chloride and then separated with CM-32 on columns or in test tubes. In 0.05 M sodium acetate pH 6.0, arylsulfatase A is not absorbed while arylsulfatase B is retained by the resin. The arylsulfatase B is then eluted from the resin with 0.3 M sodium chloride. The arylsulfatase A activity obtained from normal leukocytes and fibroblasts is linear for the initial 10 minutes of the reaction, is stimulated 3-fold by 6 mM lead acetate and inhibited 80% by 0.24 mM silver nitrate. After separation with CM-32, the arylsulfatase B activity is stimulated 3-fold by Triton X-100 (0.1%). Arylsulfatase A but not arylsulfatase B is destroyed by heat (60 degrees). Both leukocyte and fibroblast arylsulfatase A activity was reduced to 11% of control values in metachromatic leukodystrophy. Essentially no arylsulfatase B activity was detected in cells from patients with Maroteaux-Lamy syndrome. Metachromatic leukodystrophy heterozygotes but not Maroteaux-Lamy syndrome heterozygotes can also be distinguished by this method. A heat inactivation technique utilizing the differential thermal stabilities of the two enzymes for diagnosis of patients with Marotezux-Lamy syndrome is also described. The advantages of these 4-methylumbelliferyl sulfate assay procedures over the p-nitrocatechol sulfate method of assay are greater sensitivity, selectivity for the desired enzyme and potential for use in large scale testing.

Topics: Arylsulfatases; Cerebroside-Sulfatase; Chondro-4-Sulfatase; Drug Stability; Electrophoresis, Cellulose Acetate; Fibroblasts; Humans; Hydrogen-Ion Concentration; Hymecromone; Isoenzymes; Kinetics; Leukocytes; Leukodystrophy, Metachromatic; Methods; Mucopolysaccharidoses; Mucopolysaccharidosis VI; Skin; Sulfatases