Characteristics of kinetics of the enzymatic oxoglutarate dehydrogenase reaction in a system with 2,6-dichlorophenolindophenol

The 2-oxoglutarate: 2,6-dichlorophenolindophenol (DCPIP)--oxidoreductase reaction catalyzed by the oxoglutarate dehydrogenase complex from bovine adrenal glands corresponds to the kinetic mechanism of a "ping-pong" type. There are signs of positive cooperativity of the oxoglutarate dehydrogenase interaction with the substrate and negative cooperativity of that with the electron acceptor. The half-maximal rate of the model reaction is provided by 0.01 mM concentrations of 2-oxoglutarate and DCPIP. The exceeding of the DCPIP optimum concentration (0.1 mM) results in the enzyme inhibition.