The sensitivity of the exchange reactions of tricarboxylate, 2-oxoglutarate and dicarboxylate transporting systems of rat liver mitochondria to inhibition by 2-pentylmalonate, p-iodobenzylmalonate, and benzene 1,2,3-tricarboxylate.

Abstract

A new specific inhibitor, benzene 1,2,3‐tricarboxylate is described for the tricarboxylate transporting system in rat liver mitochondria. This compound, together with the ibhibitors 2‐pentylmalonate and 2‐p‐iodobenzylmalonate, has been used to elucidate the exchange reactions of the citrate, 2‐oxoglutarate and malate transporting system in rat liver mitochondria. It is proposed that both the 2‐oxoglutarate and citrate transporting systems are able to catalyse l‐malate/l‐malate exchange in addition to the l‐malate/l‐malate exchange catalysed by the dicarboxylate transporting system. p‐Iodobenzylmalonate was found to inhibit all three transporting systems investigated. The implications of these findings are discussed.