Effects of Cobalt on Mitochondrial Respiration

Abstract

Dingle, Heath, Webb, and Daniel have suggested that the toxicity of cobalt (II) is due to inhibition of keto-acid oxidation¹. This hypothesis was supported by the finding that cobalt (II) inhibited oxidation of α-ketoglutarate and pyruvate by rat liver mitochondria during a prolonged incubation without the addition of phosphate acceptor¹. Since prolonged incubation is deleterious to mitochondria², these inhibitory effects of cobalt (II) may have been an artefact. Results obtained in our laboratory show that cobalt (II) does not inhibit oxidation of α-ketoglutarate, β-hydroxybutyrate, or pyruvate plus malate during brief, polarographic experiments. Succinate oxidation was stimulated by cobalt (II) under some conditions and inhibited under others.