Oxidative phosphorylation. Biochemical effects and properties of trialkyltins.

Many workers have produced evidence that in rat-liver mitochondria oxidative phosphorylation, adenosine triphosphatase and swelling are related activities (for reviews see Lehninger, 1962a; Racker, 1961). Oxidative phosphorylation of ratliver mitochondria is inhibited by low concentrations of trialkyltins (Aldridge & Cremer, 1955; Aldridge, 1958; Aldridge & Threlfall, 1961; Moore & Brody, 1961a). Adenosine-triphosphatase activity stimulated by 2,4-dinitrophenol and the [32P]phosphate-ATP exchange reaction, both of which are considered to involve some of the reactions of oxidative phosphorylation, are inhibited by the same concentrations of trialkyltins that inhibit oxidative phosphorylation. Adenosinetriphosphatase activity is also stimulated by trialkyltins (Aldridge, 1958), but the degree to which it is stimulated varies with the particular trialkyltin and is never more than 40% of the activity obtainable with 2,4-dinitrophenol. In the present paper it is shown that trialkyltins cause swelling of mitochondria and that this occurs at the same concentrations that cause stimulation of adenosine-triphosphatase activity and inhibition of oxidative phosphorylation. The effects of trialkyltins on other biochemical systems and also their chemical properties have been studied to try to gain some insight in chemical terms of their activity against oxidative phosphorylation.