Streptolydigin, an inhibitor of oxidative phosphorylation in rat liver mitochondria.

Streptolydigin interferes with oxidative phosphorylation in rat liver mitochondria. The agent acts primarily as an uncoupler of respiration-associated phosphorylation but also impairs respiration to various degrees depending on the substrate. Streptolydigin partially inhibits electron flow at a point past the cytochrome b and prior to the cytochrome c reduction site. Streptolydigin also inhibits the function of the enzyme ribonucleic acid polymerase in whole bacterial cells and cell-free systems. The streptolydigin concentrations that cause effective inhibition of ribonucleic acid polymerase in cell-free systems are approximately 10 times less than those required to inhibit oxidative phosphorylation in mitochondria.