Sphingomyelinase activities in cultured skin fibroblasts from patients with Niemann-Pick Disease.
Sphingomyelinase activity in cultured skin fibroblasts from a fetus affected with infantile-type Niemann-Pick disease was 0.5% of control activity; the activities in cells from two patients with adult-type disease (Cases 2 and 3) were 5.0% and 59.0%. Sphingomyelinase activiy was separated into three peaks (I-III) by isoelectric focusing. The isoelectric points were 4.5, 4.9, and 5.2 for peaks I, II, and III, respectively. The three peaks in the Case 2 cells were drastically reduced; only a very small peak could be distinguished (pI of 4.7). On the other hand, three peaks were observed in the Case 3 cells. Peak I had a pI of 4.4, peak II a pI of 4.7, and peak III a pI of 5.2. Peak I was found at near normal level, but both peaks II and III were markedly reduced. Sphingomyelinase in the peak I fraction obtained from isoelectric focusing in Case 3 cells was found to have the same Km value as that in control cells.
D000328:Adult; D002478:Cells, Cultured; D002648:Child; D005260:Female; D005333:Fetus / Q000166:cytology; D005347:Fibroblasts / Q000201:enzymology; D014644:Genetic Variation; D006801:Humans; D007525:Isoelectric Focusing; D008297:Male; D009542:Niemann-Pick Diseases / Q000201:enzymology* / Q000473:pathology; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D012867:Skin / Q000201:enzymology* / Q000473:pathology; D013108:Sphingomyelin Phosphodiesterase / Q000032:analysis / Q000378:metabolism*
D010727:Phosphoric Diester Hydrolases; D013108:Sphingomyelin Phosphodiesterase