title: Evidence that neutral sphingomyelinase of cultured murine neuroblastoma cells is oriented externally on the plasma membrane.
abstract: The activity of the neutral, Mg2+-stimulated sphingomyelinase of cultured neuroblastoma cells (N1E-115) is enriched in the plasma membrane fraction and is reduced following treatment of intact or broken cells with trypsin, alpha-chymotrypsin, papain, and protease. Two protease-sensitive enzymes of the cell interior (lactate dehydrogenase and NADPH-cytochrome c reductase) are not affected by protease treatment of intact cells. These results indicate that the neutral, Mg2+-stimulated sphingomyelinase is oriented externally on the plasma membrane of the cultured neuroblastoma cell.
mesh_terms: D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology*; D002918:Chymotrypsin / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000037:antagonists & inhibitors; D008274:Magnesium / Q000494:pharmacology; D051379:Mice; D009251:NADPH-Ferrihemoprotein Reductase / Q000037:antagonists & inhibitors; D009447:Neuroblastoma / Q000201:enzymology*; D010206:Papain / Q000494:pharmacology; D010447:Peptide Hydrolases / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014357:Trypsin / Q000494:pharmacology
chemical_list: D007770:L-Lactate Dehydrogenase; D009251:NADPH-Ferrihemoprotein Reductase; D010727:Phosphoric Diester Hydrolases; D013108:Sphingomyelin Phosphodiesterase; D010447:Peptide Hydrolases; D002918:Chymotrypsin; D014357:Trypsin; D010206:Papain; D008274:Magnesium