Die Permeabilität der Erythrocytenmembran für organische Anionen

Summary

The rate of exchange of a series of carboxylic acid anions with intracellular chloride ions across the beef red cell membrane has been measured. The results support the view that most of the monocarboxylic anions penetrate through the lipid phase whereas the dicarboxylic acids (up to glutaric acid) penetrate through water filled channels.

An attempt has been made to estimate the diameter of these pores by applying the following hypothesis.

The steric hindrance of molecules of equal rotational volume but different shape should be of the same order of magnitude if the diameter of the sphere enclosing the rotational volume is less than the pore diameter. If the diameters of the spheres comprising the rotational volumes of the penetrating particles exceed the pore diameter, differences of shape of molecules having equal rotational volumes should result in drastic differences of steric hindrance.

The interpretation of our results on dibasic carboxylic acids in terms of this hypothesis leads to a value of the pore radius of between 3,8–4,5 Å.

The meaning of the term “diffusion through water filled channels” has been discussed.