title: [Action of bivalent cations on the alkaline phosphatase activity of intestinal microvilli. Influence of pH and substrate].
abstract: At alkaline or neutral pH and with PNPP or ATP as substrates, the effect of cations on alkaline phosphatase of jejunal microvilli was shown to differ, i.e. Mg++ had an activating effect at high concentrations, Zn++ slightly inhibiting, Ca++ and Co++ were inactive at all concentrations. At neutral pH with PNPP as a substrate, Mg++ and Co++ were active, Ca++ inactive and Zn++ slightly inhibiting at high concentrations. Using ATP as a substrate, all four cations were activators at all concentrations studied (0.2 to 5 mM). In the latter physiological conditions (pH and substrate), similar effects of the cations were observed with microvilli from other segments of rat small intestine.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology; D003035:Cobalt / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007583:Jejunum / Q000187:drug effects / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D008670:Metals / Q000494:pharmacology*; D008871:Microvilli / Q000187:drug effects / Q000201:enzymology; D009596:Nitrophenols / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D015032:Zinc / Q000494:pharmacology
chemical_list: D002413:Cations, Divalent; D008670:Metals; D009596:Nitrophenols; D009943:Organophosphorus Compounds; C008644:nitrophenylphosphate; D003035:Cobalt; D000255:Adenosine Triphosphate; D000469:Alkaline Phosphatase; D008274:Magnesium; D015032:Zinc; D002118:Calcium
vernacular_title: Action des cations bivalents sur l'activité de la phosphatase alcaline des microvillosités intestinales. Influence du pH et du substrat.