Inhibition of H(+)-transporting ATPase, Ca(2+)-transporting ATPase and H+/K(+)-transporting ATPase by strophanthidin.
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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Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors*; D005753:Gastric Mucosa / Q000201:enzymology; D066298:In Vitro Techniques; D007700:Kinetics; D009492:Neurospora crassa / Q000201:enzymology; D054328:Proton Pump Inhibitors; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D013327:Strophanthidin / Q000494:pharmacology*; D013552:Swine
D054328:Proton Pump Inhibitors; D013327:Strophanthidin; D006180:Proton-Translocating ATPases; D000252:Calcium-Transporting ATPases