title: [The effect of magnesium ions on the two-stage kinetics of superprecipitation and ATPase activity of natural actomyosin].
abstract: The effect of magnesium ions on the two-stage kinetics of superprecipitation (SPP) and ATP activity of natural skeletal muscle actomyosin was studied. It was found that the changes in the ratios of two independent steps of SPP and ATPase activity are mainly induced by the Mg-ATP2- complex, but not by free Mg2+. These changes in the kinetics of SPP and ATPase are regarded as being due to the shift in the dynamic equilibrium between the two types of the actomyosin complexes in solution, each of which is characterized by different reaction mechanisms. The role of the Mg-ATP2(-)-induced alteration of at least two structural-and-functional states of actomyosin in muscle contractibility is discussed.
authors: B A
authors: BA
authors: Tikunov
mesh_terms: D000205:Actomyosin / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D011232:Chemical Precipitation; D006868:Hydrolysis; D066298:In Vitro Techniques; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D051381:Rats
chemical_list: D000205:Actomyosin; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D008274:Magnesium
vernacular_title: Deĭstvie ionov magniia na dvustadiĭnuiu kinetiku superpretsipitatsii i ATPazy natural'nogo aktomiozina.