title: Diagnosis of Niemann-Pick disease using a simple and sensitive fluorimetric assay of sphingomyelinase activity.
abstract: Phosphodiesterase activity of cultured cells was determined with bis-(4-methylumbelliferyl) phosphate as substrate. In the presence of Triton X-100 an acid component was evident and results indicated that this enzyme was identical with sphingomyelinase. Acid phosphodiesterase activity was specifically inhibited by sphingomyelin. In fibroblasts from patients with Niemann-Pick diseases types A, B and C, acid phosphodiesterase activity was deficient whereas neutral activity was normal. Neutral activity could, however, be removed by acid precipitation or by binding to DEAE-cellulose. Hence a simple and sensitive fluorimetric method is described for the assay of sphingomyelinase activity in the diagnosis of Niemann-Pick disease.
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D004796:Clinical Enzyme Tests; D005347:Fibroblasts / Q000201:enzymology; D005470:Fluorometry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D009542:Niemann-Pick Diseases / Q000175:diagnosis*; D010726:Phosphodiesterase Inhibitors; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism*; D013109:Sphingomyelins / Q000494:pharmacology
chemical_list: D010726:Phosphodiesterase Inhibitors; D013109:Sphingomyelins; D010727:Phosphoric Diester Hydrolases; D013108:Sphingomyelin Phosphodiesterase