title: [Kinetics of Mg2+-dependent CF1-ATPase in the presence of stimulators].
abstract: A kinetic study of ATP hydrolysis by CF1-ATPase from chloroplasts in the presence of optimal concentrations of the stimulators, sodium sulfite and ethyl alcohol, has been carried out. At MgCl2/ATP ratios more than 1 the reaction kinetics obey the Michaelis--Menten equation. At ATP excess the kinetics are of the second order with respect to Mg2+. The data obtained are consistent with the hypothesis on the formation of an enzyme substrate Mg.CF1-MgATP complex containing beside Mg-ATP substrate Mg2+. The dependence of the maximal rate of the reaction on pH was studied. Two active groups with pK of 6.3 and 8.9 were revealed. The group responsible for Mg+2 binding to the enzyme has a pK of 8.3. The possible nature of the active groups of the enzyme is discussed.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D002736:Chloroplasts / Q000201:enzymology*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D010086:Oxidative Phosphorylation Coupling Factors / Q000378:metabolism*; D010944:Plants / Q000201:enzymology; D006180:Proton-Translocating ATPases
chemical_list: D010086:Oxidative Phosphorylation Coupling Factors; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D006180:Proton-Translocating ATPases; D008274:Magnesium
vernacular_title: Kineticheskoi issledovanie Mg2+-zavisimoĭ CF1-ATPazy v prisutstvii stimuliatorov.