On the role of K+ on succinic dehydrogenase activity

The effect of potassium ions on succinic dehydrogenase activity of mitochondria was studied. The results showed that in these organelles K+ induces inhibition of the respiratory control; moreover, in submitochondrial particles potassium inhibits the rate of oxidation of succinate. The results showed also that K+ does not changes the Km for succinate but diminishes the Vmax. In addition, the data provide evidence that mitochondria oxidizing glutamate-malate in a sucrose medium show a higher activity of succinate dehydrogenase than mitochondria incubated in KCl.