Effect of some lipophilic substances on mitochondrial ATPase

This work reports a study about the influence of some lipophilic substances like cholesterol, calciferol and tocopherol on the ATP-hydrolase activity in mitochondria. It is found that the steroids cholesterol and calciferol inhibit ATPase activity and behave like uncompetitive factors towards the enzymatic kinetics. Tocopherol, instead, affects significantly only the DCCD sensitivity of ATPase. Such effects are very probably due to the action of the physico-chemical state of th mitochondrial membrane produced by these lipophilic compounds.