[Comparison of the effects of some perminductors on mitochondria and chloroplasts].

The effects of valinomycin, gramicidins A and S, melittin and the protonophore 3,5-di-tert-butyl-4-hydroxybenzylidenmalononitrile on rat liver mitochondria and pea chloroplasts during active electron transport were studied. The canalogenes melittin and gramicidin S as well as gramicidin A and the protonophore increase the proton conductance of the inner mitochondrial membrane and chloroplast tylakoid membrane. The curve for the dependence of the canalogene effects on their concentration is S-shaped for both types of the organelles. Valinomycin reveals no protonophore activity and at high concentrations inhibits electron transport in both types of the coupling membranes. The uncoupling activity of gramicidin A and canalogenes and the inhibiting activity of valinomycin do not depend on the type of organelles when the concentration of these compounds is expressed as concentration in the membrane lipid matrix. At the same time the activity of the protonophore in chloroplasts is 6 times less than that in mitochondria. It is assumed that this difference in the protonophore activity is due to the differences in the mechanism of coupling of electron transport rather than to the peculiarities of lipid composition of mitochondria and chloroplasts. The lack of dependence of activity of peptide perminductors on the membrane lipid composition can probably be due to the fact that their effects is localized in the carbohydrate moiety of the lipid bilayer and does not involve the polar "heads" of the lipids.