title: Studies on inorganic pyrophosphatase using imidodiphosphate as a substrate.
abstract: Baker's yeast inorganic pyrophosphatase has been found to catalyze Mg2+-dependent hydrolysis of imidodiphosphate yielding phosphate and amidophosphate. The reaction proceeds linearly in the presteady state. The catalytic constant is maximal at pH 9.0 and equals 0.5 min-1. Kinetic titrations of the enzyme with imidodiphosphate and Mg2+ have provided direct evidence for the involvement of three Mg2+ per active site in the transition state of the pyrophosphatase reaction.
mesh_terms: D001665:Binding Sites; D004164:Diphosphonates / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism / Q000494:pharmacology; D010710:Phosphates / Q000378:metabolism; D011755:Pyrophosphatases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
chemical_list: D004164:Diphosphonates; D010710:Phosphates; C016514:imidodiphosphonic acid; D011755:Pyrophosphatases; D008274:Magnesium