[Conductance of model proteolipid membranes]

Artificial membranes were reconstructed from differently purified proteolipids (PL) of cattle brain white matter. The related lipids had different quantitative (72, 50-45 and 15-8%) and qualitative content. Conductance of the artificial membranes of all three types of PL in 0.1 M solutions of alkaline metal chlorides were 2-3 orders above that of bilayer membrane of lecithin and brain phospholipids. In all the cases the PL membranes with 85-92% protein content had the highest conductance, and those with 28% protein content--the lowest. Introduction of liposomes of PL and lecithin mixture to one side of the bilayer lecithin membrane brought about a gradual increase of its conductance up to a definite high level. The membranes made of all three types have specific conductance to monovalent cations which are arranged in the following order: Na+ greater than K+ greater than Cs+ greater than Li+.