Inhibitory Action of Trialkyltin Compounds on Oxidative Phosphorylation in Mitochondria*

Abstract

Trialkyltin compounds inhibited the mitochondrial respiration stimulated by ADP and the synthesis of ATP but affected little the state 4 respiration. Tri-n-butyltin chloride inhibited P₁³²-ATP exchange reaction and DNP-induced ATPase activity to the same extent as the inhibition to oxidative phosphorylation. Inhibitory potency of trialkyltin derivatives to the phosphorylating respiration was compared. A stoichiometric inhibitory pattern between TBTC and mitochondria was demonstrated. TBTC did not inhibit the DNP-stimulated respiration at the concentration which was sufficient to the inhibition to the phosphorylating respiration. From the above results, the mechanisms of action of trialkyltins were discussed.