title: The bile salt activation of leucocyte sphingolipid hydrolase activity and the modifying effects of triton X-100.
abstract: The activation of sphingomyelinase, galactosyl- and lactosylceramide beta-galactosidases, GM1, beta-galactosidase, cerebroside sulphate sulphatase, trihexosylceramide alpha-galactosidase and globoside beta-hexosaminidase by a number of bile salts was studied. Most of the salts examined, except glycolithocholate and deoxycholate, were effective activators of enzyme activity. Pure, but not crude, taurocholate elicited poor trihexosylceramide alpha-galactosidase and cerebroside sulphate sulphatase activities. The bile salt activation was often dependent on a number of parameters including the bile salt concentraion, pH, protein to bile salt ratio, and the nature of the enzyme preparation. In the absence of bile salts, Triton X-100 induced little activity of any of the hydrolases except sphingomyelinase; in their presence however, Triton either promoted or inhibited the activation depending on the enzyme. Our data suggest that bile salt structure is an important factor in determining the degree of activation of individual hydrolases and that this may be due to intramicellar lipid substrate/bile salt interactions, which either facilitate or inhibit the corresponding enzyme reaction.
mesh_terms: D000328:Adult; D001647:Bile Acids and Salts / Q000494:pharmacology*; D002553:Cerebroside-Sulfatase / Q000378:metabolism*; D004789:Enzyme Activation; D005260:Female; D005696:Galactosidases / Q000378:metabolism*; D005698:Galactosylceramidase / Q000378:metabolism; D006596:Hexosaminidases / Q000378:metabolism; D006801:Humans; D007962:Leukocytes / Q000201:enzymology*; D008297:Male; D017830:Octoxynol; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000494:pharmacology*; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism*; D013429:Sulfatases / Q000378:metabolism*; D000519:alpha-Galactosidase / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D001647:Bile Acids and Salts; D011092:Polyethylene Glycols; D017830:Octoxynol; D010727:Phosphoric Diester Hydrolases; D013108:Sphingomyelin Phosphodiesterase; D013429:Sulfatases; D002553:Cerebroside-Sulfatase; D005696:Galactosidases; D006596:Hexosaminidases; C027255:globoside-beta-hexosaminidase; C027258:lactosylceramide beta-galactosidase; C027256:trihexosylceramide alpha-galactosidase; D000519:alpha-Galactosidase; C021502:acid beta-galactosidase; D001616:beta-Galactosidase; D005698:Galactosylceramidase