Abstract
The action of salicylate on various reactions associated with the oxidative phosphorylation system of the respiratory chain of mitochondria has been investigated. The reactions studied were: (a) the [32P]P1-ATP exchange reaction, (b) the P1-H218O exchange, and (c) ATPase activity.Addition of salicylate to mitochondrial suspensions resulted in inhibition of both exchange reactions accompanied by a stimulation of ATPase. 2,4-Dinitrophenol had a qualitatively similar action but on a quantitative basis was found to be approx. 100 times as potent as salicylate with regard to inhibition of exchange reactions, and at a given level of inhibition of the [32P]P1-ATP exchange reaction resulted in greater stimulation of ATPase activity.The effects of other compounds chemically or pharmacologically similar to salicylate were investigated. None of the compounds approached salicylate or 2,4-dinitrophenol in their ability to depress [32P]P1-ATP exchange or stimulate ATPas activity.Under appropriate conditions human erythrocyte hemolysates or the 105400 × g supernatant fraction of rat-liver homogenates were found to catalyze a [32P]P1-ATP exchange reaction. These exchange reactions were found to be insensitive to salicylate or 2,4-dinitrophenol.
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