The Formation and Isolation of an Arsenylated Component of Rat Liver Mitochondria

Studies are described which show that when intact rat liver mitochondria are incubated with 74As-inorganic arsenate a new radioactive substance is produced which has been isolated and shown to possess properties that would be expected for a stable low molecular weight arsenate ester. The formation of this new compound by mitochondria is inhibited by KCN, 2,4-dinitrophenol, and oligomycin, suggesting that a functional electron transport chain and at least part of the coupling reactions of oxidative phosphorylation are required. The relationship of the new arsenylated compound to the mechanism of oxidative phosphorylation is unclear, and studies designed to clarify this aspect of the research are in progress.