A fluorimetric assay of steroid sulphatase in leukocytes: evidence for two genetically different enzymes with arylsulphatase C activity.
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.
van Diggelen
O P
OP
Department of Clinical Genetics, Erasmus University, Rotterdam, The Netherlands.
Konstantinidou
A E
AE
Bousema
M T
MT
Boer
M
M
Bakx
T
T
Jöbsis
A C
AC
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
C019492:4-methylumbelliferyl sulfate; D006923:Hymecromone; D003687:Dehydroepiandrosterone; D013429:Sulfatases; D001192:Arylsulfatases; D043266:Steryl-Sulfatase