1. A study of the 18O-exchange reactions catalyzed by cardiac myosin and its subfragment 1.
- Author
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Panteleeva NS, Ivanov GG, Karandashov EA, Krasovskaya IE, and Kuleva NV
- Subjects
- Actomyosin metabolism, Adenosine Triphosphatases metabolism, Adenosine Triphosphate metabolism, Animals, Dogs, Energy Metabolism, Humans, Magnesium metabolism, Myosin Subfragments, Rabbits, Myocardial Contraction, Myocardium enzymology, Myosins metabolism, Oxygen Consumption, Peptide Fragments metabolism
- Abstract
Isotope-exchange reactions (H2(18)O in equilibrium with KH2PO4) during ATP hydrolysis catalyzed by myosin and its subfragment 1 from rabbit, dog, and human cardiac muscle were studied. All preparations of myosin and subfragment 1 in the presence of Mg2+ catalyzed two types of 18O-exchange reactions similar to those of skeletal muscle: intermediate and direct 18O exchange. The dependences of both reactions on divalent metals and nucleotides were studied. Data on 18O exchange of subfragment 1 from rabbit, dog, and human cardiac muscle were obtained for the first time. They indicate the similarity of molecular mechanisms of ATP energy use in cardiac and skeletal muscle contraction.
- Published
- 1982
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