Effectors of three beta-glucosidases from human liver.
1. A third beta-glucosidase from human liver has been isolated using a mild (0.02-0.10%) Triton X-100 extraction of the exhaustively washed high speed (200,000 X g, 30 min) particulate fraction, QAE-Sephadex and concanavalin A-Sepharose chromatography. This new beta-glucosidase, referred to as TX beta-glucosidase, possesses a distinctive set of chemical properties such that it is similar to both, glucocerebrosidase and cytoplasmic beta-glucosidase, but it is not identical to either enzyme. 2. The TX beta-glucosidase hydrolyzes glucocerebroside as well as the beta-D-glucose, beta-D-galactose, beta-D-fucose, beta-D-xylose and alpha-L-arabinose derivatives of 4-methylumbelliferone. Like the cytoplasmic beta-glucosidase, the TX beta-glucosidase is inhibited by bile salts, and unaffected by conduritol B epoxide and heat stable activator protein. 3. All three beta-glucosidases were inhibited by N-hexylpsychosine, and all showed the same, mixed type inhibition kinetics, indicating a common hydrophobic binding site in all three enzymes. 4. The TX beta-glucosidase, which constitutes only a few percent of the total beta-glucosidase activity of human liver, is absent from liver from two cases of neurologic Gaucher disease and present in reduced amounts in a third case with CNS disease. Liver from a case of type 1 Gaucher disease contained normal amounts of the TX beta-glucosidase.
D001647:Bile Acids and Salts / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005678:G(M2) Ganglioside / Q000494:pharmacology; D005776:Gaucher Disease / Q000201:enzymology*; D005959:Glucosidases / Q000378:metabolism*; D005962:Glucosylceramidase / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D001647:Bile Acids and Salts; D007527:Isoenzymes; D005678:G(M2) Ganglioside; D005959:Glucosidases; D001617:beta-Glucosidase; D005962:Glucosylceramidase