Diagnosis of adult Gaucher disease: use of a new chromogenic substrate, 2-hexadecanoylamino-4-nitrophenyl-beta-D-glucopyranoside, in cultured skin fibroblasts.
Gaucher disease is a group of lipid storage diseases in which the glycosphingolipid glucocerebroside accumulates in tissues because of deficiency of the enzyme glucocerebrosidase. Radioactively labelled glucocerebroside and the artificial fluorogenic substrate 4-methylumbelliferyl-beta-D-glucopyranoside are commonly used for its diagnosis. We studied the use of a new chromogenic substrate, 2-hexadecanoylamino-4-nitrophenyl-beta-D-glucopyranoside in cultured skin fibroblasts. The amount of reaction product, 2-hexadecanoylamino-4-nitrophenol, increased linearly with incubation time for at least 4 h and was proportional to the amount of fibroblast protein added up to 150 micrograms per incubation. The pH optimum was 4.8. The Km was 0.19 mmol/l. The mean activity of control cultured skin fibroblasts was 22.9 +/- 5.4 nmol of product formed per mg fibroblast protein per hour under standard conditions. Cultured skin fibroblasts from patients with adult non-neuropathic Gaucher disease had reduced activity, 6.4 +/- 2.4 nmol/mg/h or 28% of control activity. This compared well with mean enzyme activity in the same patients determined using the natural substrate, [14C]glucocerebroside: 28% of control activity. Heterozygotes had reduced activity with the new substrate.
D000328:Adult; D002478:Cells, Cultured; D004796:Clinical Enzyme Tests / Q000379:methods; D005776:Gaucher Disease / Q000175:diagnosis* / Q000235:genetics; D005959:Glucosidases / Q000032:analysis*; D005960:Glucosides; D005962:Glucosylceramidase / Q000032:analysis*; D006027:Glycosides; D006579:Heterozygote; D006651:Histocytochemistry; D006801:Humans; D007585:Jews; D012867:Skin / Q000201:enzymology*
D005960:Glucosides; D006027:Glycosides; C013552:2-hexadecanoylamino-4-nitrophenyl-D-glucopyranoside; D005959:Glucosidases; D005962:Glucosylceramidase