Variation of arylsulphatase A: comparative studies of arylsulphatase A with synthetic and natural substrates in three families with metachromatic leucodystrophy.
Arylsulphatase A activity was measured in leucocytes and cultured tibroblasts from individuals of three families with late infantile and adult metachromatic leucodystrophy, comparing enzyme assays with natural and two synthetic substrates including a simple and sensitive test employing 4-methylumbelliferly sulphate and AgNO3. Enzyme activities were compared with those obtained after isoelectric focusing. Arylsulphatase A values obtained for different heterozygotes were almost continuously scattered over the entire range from patient level to normal level. Nevertheless arylsulphatase A values of the heterozygotes were at least sligtly higher than the activity of diseases persons when measured with three different assays. The possibility is discussed of a crucial minimal level of residual arylsulphatase A activity necessary to avoid manifestation of the disease.
D000293:Adolescent; D000328:Adult; D002478:Cells, Cultured; D002553:Cerebroside-Sulfatase / Q000032:analysis* / Q000652:urine; D002648:Child; D002675:Child, Preschool; D005260:Female; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D007962:Leukocytes / Q000201:enzymology; D007966:Leukodystrophy, Metachromatic / Q000201:enzymology* / Q000652:urine; D008297:Male; D008722:Methods; D013429:Sulfatases / Q000032:analysis*
D013429:Sulfatases; D002553:Cerebroside-Sulfatase