Inhibition of H(+)-transporting ATPase, Ca(2+)-transporting ATPase and H+/K(+)-transporting ATPase by strophanthidin. |
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Authors: | K Y Xu |
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Institution: | Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510. |
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Abstract: | Studies of the effect of strophanthidin on H(+)-transporting ATPase, Ca(2+)-transporting ATPase and H+/K(+)-transporting ATPase activities are reported. Inhibition observations and kinetic results suggest the existence of a common digitalis aglycone binding site located on the extracellular surface of the enzyme, which is affected competitively by the binding of potassium to H(+)-transporting ATPase, Ca(2+)-transporting ATPase, as well as H+/K(+)-transporting ATPase and Na+/K(+)-transporting ATPase. This may lead to a better understanding of the mechanism of the pharmacological action of cardiac glycosides and imply the possibility that the positive inotropic effect may result from the inhibition of both Ca(2+)-transporting ATPase and Na+/K(+)-transporting ATPase. |
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