Uncoupling of oxidative phosphorylation in mitochondria from fatty livers

Abstract

The author confirms that uncoupling of oxidative phosphorylation occurs in both homogenates and mitochondria from livers and kidneys of rats after treatment with distilled water. Uncoupling of oxidative phosphorylation was found also to occur in both homogenates and mitochondria from fatty livers, without previous treatment with water. ATPase activity, and also pyrophosphatase, acid and alkaline phosphatases, and the hydrolysis of fructose-6-monophosphate were investigated in order to see if the observed uncoupling could be referred to an increase of these phosphatase activities. Increase of ATPase and of acid and alkaline phosphatases activities were notices. A modification of the distribution of inorganic pyrophosphatase and of both acid and alkaline phosphatases within the cell was found. The extent of increase of phosphatase activities does not seem, however, sufficient for explaining the uncoupling of phosphorylations from oxidations. The analysis of phosphorylated intermediates formed during the oxidative phosphorylation reaction showed in both “water-treated” and “fatty” preparations a decrease of the formation of ATP, decrease of the formation of fructose-6-monophosphate, accumulation of ADP and normal rate of disappearance of added AMP. On the base of these observations, the author thinks that uncoupling of oxidative phosphorylation is due to the inefficiency of the formation of ATP from ADP + P.