INACTIVATION OF ALPHA-KETOGLUTARATE DEHYDROGENASE DURING OXIDATIVE DECARBOXYLATION OF ALPHA-KETOADIPIC ACID

Alpha-Ketoglutarate dehydrogenase was inactivated irreversibly and com pletely during oxidation of alpha-ketoadipic acid. The inactivation wa s revealed both in the model system with ferricyanide and in the overa ll reaction catalyzed by the alpha-ketoglutarate dehydrogenase complex . Neither substrate depletion nor product accumulation induced the ina ctivation. The results obtained were compared with recent data on the enzyme inactivation during oxidation of alpha-ketoglutaric acid. The d ifferences in the inactivation kinetics observed with the two substrat es of the enzyme were analyzed. They seem not to reflect the different mechanisms of the inactivation, but, rather, depend on the changes in the rates of the individual stages of the process.