title: Membrane-bound potassium and magnesium ion-stimulated inorganic pyrophosphatase from roots and cotyledons of sugar beet (Beta vulgaris L).
abstract: 1. The 25 000-30 000 X g fraction from sugar beet leaf or roots contains, together with (Na+ plus K+)-activated ATPase, also K+-stimulated inorganic pyrophosphatase. 2. This inorganic pyrophosphatase is also stimulated by Rb+ and to a lesser degree by Li+ and Na+. 3. Na+ is at the same time an inhibitor to the K+-stimulation of the inorganic pyrophosphatase. 4. No signs of synergism for (Na+ plus K+) were found. 5. Optimum pH was at about 8.5.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D002414:Cations, Monovalent; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D010710:Phosphates; D010944:Plants / Q000201:enzymology*; D011188:Potassium / Q000494:pharmacology*; D011755:Pyrophosphatases / Q000378:metabolism*; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D002414:Cations, Monovalent; D010710:Phosphates; D000251:Adenosine Triphosphatases; D011755:Pyrophosphatases; D008274:Magnesium; D011188:Potassium