title: Stimulation by ATP of alkaline phosphatase in placental plasma membranes.
abstract: 1. ATP stimulated the p-nitrophenyl phosphatase activity of placental plasma membranes, with an increase in activity of approximately 100% at 5 mM ATP. The stimulation was not dependent on the presence of Mg-2-+. 2. The K-m for p-nitrophenyl phosphate was not changed by the presence of 5 mM ATP. 3. ATP hydrolysis by the plasma membrane preparation under the same assay conditions as for alkaline phosphatase was not influenced by the presence of 5 mM p-nitrophenyl phosphate. 4. Extraction of the plasma membrane preparation with n-butanol abolished the stimulatory effect of ATP, as well as Ca-2-+-activated ATPase activity.
mesh_terms: D009597:4-Nitrophenylphosphatase / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D000440:Butanols; D002118:Calcium / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006168:Guinea Pigs; D007700:Kinetics; D010920:Placenta / Q000187:drug effects / Q000201:enzymology*; D011247:Pregnancy
chemical_list: D000440:Butanols; D000255:Adenosine Triphosphate; D000469:Alkaline Phosphatase; D009597:4-Nitrophenylphosphatase; D000251:Adenosine Triphosphatases; D002118:Calcium