title: [Localization of the ATPase site of nitrogenase by isotopic oxygen exchange [180]-Pi in equilibrium with H20].
abstract: The components of the nitrogenase complex, MoFe-protein and FeMo-cofactor, possessing no ATPase or nitrogen-fixing activity, maintain the 18O-exchange at the level of 1 atom of 18O per molecule of Pi, which is inhibited by ATP. The Fe-protein complex does not catalyze the 18O-exchange. The nitrogenase components do not hydrolyze the substrates for phosphatase (p-nitrophenylphosphate, beta-glycerophosphate, glucose 1-phosphate and ribose 5-phosphate). The artificial albumin-containing MoFe- and Fe-proteins and the carboxyl group-containing proteins (albumin, hemoglobin, lysozyme) as well as sodium molibdate do not catalyze the 18O-exchange. It is assumed that the site of the ATPase center which is subjected to phosphorylation, is located on the MoFe-protein.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001395:Azotobacter / Q000201:enzymology*; D007506:Iron-Sulfur Proteins / Q000378:metabolism; D007700:Kinetics; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000378:metabolism*; D010103:Oxygen Isotopes
chemical_list: D007506:Iron-Sulfur Proteins; D010103:Oxygen Isotopes; D009591:Nitrogenase; D000251:Adenosine Triphosphatases
vernacular_title: Issledovanie lokalizatsii ATPaznogo tsentra nitrogenazy metodom izotopnogo obmena kisloroda [180]-Pi v ravnovesii H20.