title: Alkaline phosphodiesterase I release from eucaryotic plasma membranes by phosphatidylinositol-specific phospholipase C. II. The release from brush border membranes of porcine intestine.
abstract: Ectoenzyme release from porcine intestinal brush border membranes by phosphatidylinositol-specific phospholipase C of Bacillus thuringiensis was studied. Alkaline phosphodiesterase I, alkaline phosphatase and 5'-nucleotidase were released from both slices and brush border membranes. The pattern of alkaline phosphodiesterase I release was the same as that of alkaline phosphatase. The release of alkaline phosphodiesterase I induced by phospholipase C was dependent on, or proportional to, the reaction time and the concentration of phospholipase C. The Arrhenius plot for phosphodiesterase I release showed a single break at 30 degrees C for brush border membranes. Only 40% of alkaline phosphodiesterase I present in the brush border membranes were solubilized by phosphatidylinositol-specific phospholipase C treatment. The data indicate the presence of two forms of phosphodiesterase I, which are different in their sensitivity to phospholipase C. The released alkaline phosphodiesterase I had a molecular weight of 240,000 and was activated by Mg2+ and Ca2+, but strongly inhibited by EDTA.
mesh_terms: D015720:5'-Nucleotidase; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002845:Chromatography; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000201:enzymology*; D007700:Kinetics; D008871:Microvilli / Q000187:drug effects / Q000201:enzymology; D008970:Molecular Weight; D009708:Nucleotidases / Q000378:metabolism; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D043264:Phosphodiesterase I; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism* / Q000494:pharmacology*; D013552:Swine
chemical_list: D009708:Nucleotidases; D000469:Alkaline Phosphatase; D015720:5'-Nucleotidase; D010727:Phosphoric Diester Hydrolases; D043264:Phosphodiesterase I; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase