title: Spin-labeled ouabain as a probe for cardiac glycoside receptor/Na, K-ATPase.
abstract: We have synthesized a nitroxide spin-label derivative of the cardiac glycoside, ouabain. It has been tested on purified Na,K-ATPase from dog kidney as a probe to study the physico-chemical interactions of this class of drugs with receptor(s). Spin-labeled ouabain retained the biochemical properties of native ouabain as judged by dose response curves for inhibition of Na,K-ATPase activity and inhibition of [3H]-ouabain binding to receptor. Electron paramagnetic resonance spectra of the spin-labeled ouabain-Na,K-ATPase complex revealed the presence of two types of bound label with differing degrees of immobilization.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D003497:Cyclic N-Oxides / Q000138:chemical synthesis*; D004285:Dogs; D004578:Electron Spin Resonance Spectroscopy; D007679:Kidney Medulla / Q000201:enzymology*; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology; D010042:Ouabain / Q000378:metabolism*; D011955:Receptors, Drug / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: D003497:Cyclic N-Oxides; D011955:Receptors, Drug; C028996:cardiac glycoside receptors; D010042:Ouabain; C042847:4-amino-2,2,6,6-tetramethylpiperidin-1-oxy-ouabain; D000254:Sodium-Potassium-Exchanging ATPase