English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Electrical properties of black membranes from oxidized cholesterol and a strongly bound protein fraction of human erythrocyte membranes

MPS-Authors
/persons/resource/persons255902

Schubert,  Dieter
Department of Cell Physiology, Max Planck Institute of Biophysics, Max Planck Society;

External Resource
No external resources are shared
Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Lossen, O., Brennecke, R., & Schubert, D. (1973). Electrical properties of black membranes from oxidized cholesterol and a strongly bound protein fraction of human erythrocyte membranes. Biochimica et Biophysica Acta-Biomembranes, 330(2), 132-140. doi:10.1016/0005-2736(73)90217-4.


Cite as: https://hdl.handle.net/21.11116/0000-0008-9E2E-4
Abstract
1. Black lipid membranes from oxidized cholesterol show an up to 103-fold increase in electrical conductivity following the addition of a strongly bound protein fraction from human erythrocyte membranes (obtained by depolymerisation of the membranes in 90% acetic acid after removal of the loosely bound proteins by treatment with 10% acetic acid) to the surrounding solutions. The presence of protein on both sides of the membrane is a prerequisite for this effect.
2. The major part of the interactions leading to the protein-induced conductivity change is irreversible.
3. The magnitude of the conductivity change is dependent on protein concentration and on the composition of the buffers in which the membranes are formed. In the range of conditions investigated (salt concentration C=2-200mM, pH=5.5-8.5, protein concentration cp=0.001-1.0mg/ml), membrane conductivity increases strongly with increasing salt concentration and weakly with decreasing pH; the effect of shows a maximum at about 0.05 mg/ml. 4. The effect of salt concentration is about 10-fold larger in NaCl than in sodium acetate solutions. The ion transport numbers for the protein-lipid membranes were found to depend on the nature of the anion present. 5. The current-voltage curve of the membranes is nonliner both in the presence and absence of protein. 6. It is concluded that substructures of conducting sites essentially confined to one side of the lipid bilayer are formed by hydrophobic association between the lipid membrane and molecules from the protein solution. The conductivity effects described are thought to be due to an interaction of substructures situated on different sides of the membrane.