Ionics and conformational transitions of Na,K-ATPase.
Equilibrium binding studies have been carried out by spectrofluorometric precision titrations on FITC-Na,K-ATPase and employing the styryl dye RH-421 to obtain equilibrium constants and stoichiometric coefficients together with information related to competition between different binding equilibria. A new interpretation concerning the assignment of spectral properties and cation complex formation equilibria, as well as the involvement of conformational transitions, is suggested, based on a differentiation between selective and unselective alkali ion binding. The kinetics of K+ binding to the FITC-enzyme have been studied by employing a new microvolume technique consisting of flash photolysis of caged-K+.
Grell
E
E
Max-Planck-Institute for Biophysics, Frankfurt, Germany.
Warmuth
R
R
Lewitzki
E
E
Ruf
H
H
D000818:Animals; D002021:Buffers; D002412:Cations / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology; D016650:Fluorescein-5-isothiocyanate; D007668:Kidney / Q000201:enzymology; D011487:Protein Conformation; D012756:Sheep; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry* / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013552:Swine
D002021:Buffers; D002412:Cations; D000254:Sodium-Potassium-Exchanging ATPase; D016650:Fluorescein-5-isothiocyanate