| Abstract: | Kinetic analysis reveals the mainly competitive inhibition of Na+-dependent Ca2+ efflux from mitochondria by cations of monovalent metals. Potency of the inhibitory effect of metals' cations on Na+-dependent Ca2+ efflux from mitochondria matrix increases in such an order (I50, mM): Cs+ (137.11) < Rb+ (122.63) < Li+ (24.59) < Tl+ (0.541). The results of correlation analysis show that sodium ions translocation by mitochondrial exchanger and its inhibition by the cations of monovalent metals is determined by their affinity for the oxygen-containing ligands and are accompanied with the ions dehydration. Inhibition of the mitochondrial Na+/Ca2+ exchanger by monovalent metal cations is also accompanied with the inhibition of cooperative interactions of metal ions with the ionbinding centers during transport cycle, which can be one of the mechanisms of the inhibition of ions translocation by this ion-transporting system. |
