The effect of detergents on immunoprecipitability of lysosomal sphingomyelinase.

Antibodies raised against the soluble form of acid sphingomyelinase from human urine and placenta are able to precipitate about 70% of the sphingomyelinase activity present in preparations of urinary sphingomyelinase. In contrast, no precipitation of sphingomyelinase activity occurs in detergent-containing preparations from placenta or splenic membranes. The formation of immune complexes between the antibodies and urinary sphingomyelinase is inhibited if detergents are added. With the non-ionic detergent Triton X-100 significant inhibition occurs only above the critical micellar concentration of the detergent. With the anionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulphonate (Chaps) substantial inhibition is already observed below the critical micellar concentration of the detergent.