Inhibition of (Na+ + K+)-ATPase by ouabain: involvement of calcium and membrane proteins.
Treatment of plasma membrane isolated from murine plasmocytoma MOPC 173 with an EDTA-containing buffer resulted in a 300-fold increase in sensitivity of (Na+ + K+)-stimulated Mg2+-ATPase to ouabain. This phenomenon was associated with the solubilization by EDTA of phospholipid free proteins (approx. 30 000-34 000 daltons) from the cytoplasmic face of the plasma membrane and with removal of about 90% of the membrane bound Ca2+. The recovery of the original resistance to ouabain required specifically Ca2+ and was associated with a binding of the solubilized proteins to the membrane.
D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D004492:Edetic Acid / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D008565:Membrane Proteins / Q000502:physiology*; D051379:Mice; D008970:Molecular Weight; D010042:Ouabain / Q000494:pharmacology*; D010954:Plasmacytoma; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification
D008565:Membrane Proteins; D010042:Ouabain; D004492:Edetic Acid; D000254:Sodium-Potassium-Exchanging ATPase; D008274:Magnesium; D002118:Calcium