Substrate specificity of succinyl-CoA transferase from rat kidney mitochondria.

1. Succinyl-CoA: 3-oxoacid transferase (EC 2.8.3.5) from rat kidney mitochondria, purified about 200-fold, catalyses the CoA transfer from acetoacetyl-CoA to succinate, acetoacetate, maleate, glutarate and malonate; maleate proved to be a true substrate of the enzyme. 2. Double-reciprocal plots of the initial reaction rates against substrates concentrations arb best fitted by parallel lines. Inhibition by each acid product of the reaction is competitive with respect to the acid acceptor of CoA. 3. CoA-transferase from rat kidney shows similar kinetics as, but different substrate specificity than, the enzyme from other sources.