Effects of copper, cadmium, zinc and two mixtures of these metals on oxidative phosphorylation, ATPase and electron transport of isolated rat liver mitochondoria.

The effects of metals on oxdative phosphorylation, ATPase and electron transport were examined. Cadmium accelerated state 4 respiration and increased latent ATPase activity, indicating that cadmium is an uncoupler of the energy transport reaction. Cadmium did not inhibit site 1, 2 or 3 of the electron transport chain. Copper inhibited state 3 respiration, accelerated state 4 respiration, increased latent ATPase activity and decreased stimulated ATPase activity, indicating that copper is an uncoupler and effects the energy tranport reaction. Copper did not inhibit site 1, 2 or 3 of the electron transport chain. Zinc inhibited state 3 and state 4 respiration, increased latent ATPase activity, decreased stimulated ATPase activity slightly, and inhibited sites 1 and 2 of the electron tranport chain. One pair of the 3 metals had additive effects on state 3 and 4 respiratory activity and on stimulated and latent ATPase activity. A competitive reaction between copper and zinc was observed in the effects on sites 1 and 2 of the electron transport chain.