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From: "Jonathan B. Marder" <marder@agri.huji.ac.il>
Newsgroups: bionet.biophysics
Subject: Re: Dielectric constant of biomembranes
Date: Sun, 8 Feb 1998 12:23:18 +0200
Organization: Hebrew University
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Pentcho Valev wrote in message =
+ADw-6b9cmu+ACQ-d43+AEA-mserv1.dl.ac.uk+AD4-...
...
+AD4-
+AD4-1. If the dielectric constant varies ALONG the membrane and if =
Donnan
+AD4-transmembrane potential difference is established, the combination =
of the
+AD4-following two universally accepted facts: a) that the potential is
+AD4-uniform on each side of the membrane b) that the transmembrane =
potential
+AD4-difference is equal to the ratio of the surface charge density and =
the
+AD4-capacitance - leads inevitably to the incredible result that, even =
at
+AD4-(Donnan) equilibrium, there are local lateral and, accordingly,
+AD4-transmembrane fluxes of some ion, e.g. H.
+AD4-
...
Pentcho, this is really not so mysterious. There are lateral movements =
of ions until electroCHEMICAL equilibrium is reached. Once this happens, =
there will be no more net ion fluxes. I see no problem with membrane =
patches attracting concentrations of particular ions - in fact I expect =
that this is documented in the literature.




.