title: A fluorimetric assay of steroid sulphatase in leukocytes: evidence for two genetically different enzymes with arylsulphatase C activity.
abstract: Arylsulphatase C (ASC) activity in leukocytes and fibroblasts measured with 4-methylumbelliferylsulphate, is caused by at least two genetically different sulphatases. One of these is steroid sulphatase (STS). Depending on the substrate concentration, about 10-50% of the ASC activity in leukocytes can be attributed to sulphatases other than STS. Steroid sulphatase can be measured specifically with 4-methylumbelliferylsulphate as the fraction of total ASC activity which is inhibitable by dehydroepiandrosterone sulphate. Using this assay, the adjusted ASC activity in leukocytes from patients with X-linked ichthyosis was 2% of normal. Obligate heterozygotes showed reduced activity.
authors.affiliation: Department of Clinical Genetics, Erasmus University, Rotterdam, The Netherlands.
authors.forename: O P
authors.initials: OP
authors.lastname: van Diggelen
authors.forename: A E
authors.initials: AE
authors.lastname: Konstantinidou
authors.forename: M T
authors.initials: MT
authors.lastname: Bousema
authors.forename: M
authors.initials: M
authors.lastname: Boer
authors.forename: T
authors.initials: T
authors.lastname: Bakx
authors.forename: A C
authors.initials: AC
authors.lastname: Jöbsis
mesh_terms: D001192:Arylsulfatases / Q000037:antagonists & inhibitors / Q000097:blood / Q000235:genetics* / Q000378:metabolism*; D003687:Dehydroepiandrosterone / Q000494:pharmacology; D005260:Female; D005470:Fluorometry; D008040:Genetic Linkage; D006801:Humans; D006923:Hymecromone / Q000031:analogs & derivatives; D007057:Ichthyosis / Q000175:diagnosis / Q000201:enzymology; D007700:Kinetics; D007962:Leukocytes / Q000201:enzymology*; D008297:Male; D043266:Steryl-Sulfatase; D013429:Sulfatases / Q000235:genetics* / Q000378:metabolism*; D014960:X Chromosome
chemical_list: C019492:4-methylumbelliferyl sulfate; D006923:Hymecromone; D003687:Dehydroepiandrosterone; D013429:Sulfatases; D001192:Arylsulfatases; D043266:Steryl-Sulfatase