[Kinetic properties of lipoamide dehydrogenase of the oxoglutarate dehydrogenase complex of the human heart].

Kinetics of lipoamide dehydrogenase catalyzed reaction is described by Michaelis-Menten equation if concentrations of NAD and dihydrolipoamide (DLA) varied. Effective Km values were equal to 0.11 mM for NAD and 0.50 mM for DLA, respectively. Kinetic indications of positive cooperation between sites binding both NAD and DLA were manifested in presence of NADH. Apparent Ki value for NADH constituted 0.88-0.10 mM, thus demonstrating the effective regulation of the lipoamide dehydrogenase activity by end products.