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Studies on inorganic pyrophosphatase using imidodiphosphate as a substrate
Author(s) -
Smirnova Iri.,
Baykov Alexander A.,
Avaeva Svetlana M.
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)81352-7
Subject(s) - inorganic pyrophosphatase , pyrophosphatase , titration , substrate (aquarium) , chemistry , hydrolysis , catalysis , enzyme , pyrophosphatases , michaelis–menten kinetics , phosphate , inorganic phosphate , inorganic chemistry , stereochemistry , nuclear chemistry , pyrophosphate , biochemistry , enzyme assay , biology , ecology
Baker's yeast inorganic pyrophosphatase has been found to catalyze Mg 2+ ‐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 Mg 2+ have provided direct evidence for the involvement of three Mg 2+ per active site in the transition state of the pyrophosphatase reaction.