title: [Effect of calcium ions on creatine kinase systems of myocardial cells].
abstract: The kinetics of the creatine phosphokinase reaction catalyzed by different creatine phosphokinase (CPK) isoenzymes from the heart and the mechanism of the regulatory action of calcium ions on this reaction have been studied. It has been shown that the kinetic parameters of the reaction in the presence of calcium are similar to those in the presence of magnesium with the exception of the maximal rate of the reverse reaction, which is about three times lower in the presence of calcium. Calcium ions are able to exert a significant regulatory action on the CPK reaction. Simultaneous regulation of the CPK reaction by calcium and magnesium ions can be quantitatively described by a kinetic model, which takes into account the formation of complexes of adenine nucleotides with calcium and magnesium. The mechanism of the CPK reaction regulation by metal ions involves changes in concentrations of the metal -- adenine nucleotide compexes. The regulatory action of calcium on the creatine kinase reaction is the same for all CPK isoenzymes studied.
mesh_terms: D000227:Adenine Nucleotides / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D003402:Creatine Kinase / Q000378:metabolism*; D007527:Isoenzymes; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008433:Mathematics; D009206:Myocardium / Q000201:enzymology*; D051381:Rats
chemical_list: D000227:Adenine Nucleotides; D007527:Isoenzymes; D003402:Creatine Kinase; D008274:Magnesium; D002118:Calcium
vernacular_title: Vliianie ionov kal'tsiia na kreatinkinaznye sistemy kletok milorda.