Authors: Yuri N Antonenko Peter Pohl
Publish Date: 2008/03/11
Volume: 37, Issue: 6, Pages: 865-870
Abstract
Proton diffusion along the surface of a planar bilayer lipid membrane was measured by means of acid/base injection with a micropipette and recording of the kinetics of fluorescence changes of fluoresceinlabelled lipid on the surface The dimensionality of the process was assayed by fitting the kinetic curves with twodimensional 2D or threedimensional 3D diffusion equations In agreement with Serowy et al Biophys J 841031–1037 2003 lateral proton diffusion proceeded via bulk phase by means of buffer molecules as proton carriers D = 600 μm2/s under the conditions of 1 mM buffer in the solution Introduction of proton binding sites on the membrane surface led to the appearance of a considerable contribution of twodimensional proton diffusion on the membrane surface with D = 1100 μm2/s The system described can be used to study the dependence of the proton diffusion rate on the phospholipid and protein composition of the membrane
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