Inhibition of aconitase by trans-aconitate.

Bernheim (2), studying the properties of the “citric dehydrogenase” system, noted that aconitic acid (presumably the trans isomer) inhibited the reduction of methylene blue by citric acid. More recently, Morrison and Still (3), in a short report, claimed that truns-aconitic acid inhibited competitively the reaction cis-aconitate c citrate, catalyzed by the aconitase of rhubarb leaf. The present studies show that trans-aconitate is a competitive inhibitor of aconitase of animal tissues and that trans-aconitate inhibits the respiration of tissue slices and causes the accumulation of citrate by surviving kidney cortex and liver slices.