[Conformational stability of glutamate dehydrogenase and its complexes with specific ligands]

The isotermic denaturation of glutamatdehydrogenase (GDH) and its complexes with co-enzymes, substrates and allosteric regulators under the action of urea was studied. It was shown that the reaction of the enzyme with an allosteric inhibitor GTP is accompanied by a decrease in conformational stability of the catalytically active hexsamer GDH. Formation of a complex with the allosteric activator ADP increases the conformational stability of the enzyme. Studies on the isotermic unfolding of GDH in the presence of various phosphoric ethers of adenosine gave evidence that the stabilizing effect of ADP is based on the reaction of the enzyme with the adenine base of the regulator.