[Study of the mitochondrial Ca2+-transport system on lipid bilayer membranes (LBM)].

Electrical properties of BLM formed from lipid components of rat liver mitochondria were studied. The lipids were obtained after preliminary 40 second incubation of mitochondria in the medium containing succinic acid. BLM electroconductivity in the medium with calcium chloride (8--20 mM) is 10--100 times higher than the initial electroconductivity in tris-HC1 at pH 7.5, and in the presence of potassium chloride and magnesium chloride it differes little from the initial value. The transmembrane potential difference per 10-fold concentration gradient of Ca2+, Mg2+, and K+ is approximately 27 mV, approximately 15 mV and approximately 22 mV correspondingly. By means of biionic potential method the following selectivety line for cations is formed: Ca2+ greater than Sr2 greater than or equal to Mg2+ greater than K+. La3+ ions inhibit the transport of Ca2+ through the BLM studied.