The antibiotic W341C, its ion transport properties and inhibitory effects on mitochondrial substrate oxidation.

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Abstract
We have examined the ion transport properties and the inhibition of rat liver mitochondrial substrate oxidation by the antibiotic W341C. W341C was able to transport 22Na+ and 42K+ across a bulk carbon tetrachloride layer. A preference was shown for K+ transport. With equal molar antibiotic concentrations, W341C transported 42K+ at a greater rate than the K+-selective ionophore nigericin, but transported 22Na+ at a lesser rate than the Na+-selective ionophore monensin. Like nigericin, W341C was able to deplete mitochondrial K+, but not Mg2+ nor Ca2+. The inhibition of mitochondrial substrate oxidation by W341C paralleled the patterns obtained with nigericin. These data indicate that W341C is a K+-selective ionophore that inhibits mitochondrial substrate oxidation by a mechanism analogous to that of nigericin.