Type of Publication: | Journal article |
URI (citable link): | http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-41792 |
Author: | Apell, Hans-Jürgen; Marcus, Madeleine M.; Anner, Beatrice M.; Oetliker, H.; Läuger, Peter |
Year of publication: | 1985 |
Published in: | The Journal of Membrane Biology ; 85 (1985), 1. - pp. 49-63. - ISSN 0022-2631. - eISSN 1432-1424 |
DOI (citable link): | https://dx.doi.org/10.1007/BF01872005 |
Summary: |
A fluorescence method is described for the measurement of ATP-driven ion fluxes in lipid vesicles containing purified Na.K-ATPase. The membrane voltage of enzyme containing vesicles was measured by using a voltage-sensitive indocyanine dye. By addition of valinomycin the vesicle membrane is made selectively ermeable to K- so that the membrane voltage approaches the Nernst potential for K+. With constant external K+ concentration. the time course of internal K+ concentration can be continuously measured as change of the fluorescence signal after activation of the pump. The optical method has a higher time resolution than tracer-flux experiments and allows an accurate determination of initial flux rates. From the temperature dependence of active K+ transport its activation energy was determined to be 115 kJ/mol. ATP-stimulated electrogenic pumping can be measured as a fast fluorescence change when the membrane conductance is low (i.e., at low or zero valinomycin concentration). In accordance with expectation, the amplitude of the fast signal change increases with decreasing passive ion permeability of the vesicle membrane. The resolution of the charge movement is so high that a few pump turnovers can be easily detected.
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Subject (DDC): | 570 Biosciences, Biology |
Keywords: | Na,K-ATPase, reconstitution, potential sensitive dye, ion fluxes, transport kinetics, activation energy |
Link to License: | Attribution-NonCommercial-NoDerivs 2.0 Generic |
APELL, Hans-Jürgen, Madeleine M. MARCUS, Beatrice M. ANNER, H. OETLIKER, Peter LÄUGER, 1985. Optical Study of Active Ion Transport in Lipid Vesicles Containing Reconstituted Na,K-ATPase. In: The Journal of Membrane Biology. 85(1), pp. 49-63. ISSN 0022-2631. eISSN 1432-1424. Available under: doi: 10.1007/BF01872005
@article{Apell1985Optic-8334, title={Optical Study of Active Ion Transport in Lipid Vesicles Containing Reconstituted Na,K-ATPase}, year={1985}, doi={10.1007/BF01872005}, number={1}, volume={85}, issn={0022-2631}, journal={The Journal of Membrane Biology}, pages={49--63}, author={Apell, Hans-Jürgen and Marcus, Madeleine M. and Anner, Beatrice M. and Oetliker, H. and Läuger, Peter} }
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