[Structural organization of a hexamer of glutamate dehydrogenase. 3. Effect of the coenzyme and substrate on the urea-induced dissociation and inactivation of the hexamer].
Effects of coenzyme (NADH) and substrate (2-oxoglutarate) on the urea-induced dissociation and inactivation of immobilized phosphopyridoxyl derivative of bovine liver glutamate dehydrogenase (L-glutamate-NAD(P)-oxidoreductase, EC 1.4.1.3) have been studied. Urea at concentration 3.0 to 4.0 M in the presence of NADH induced dissociation of the enzyme's hexamer to catalytically inactive immobilized dimer. In the presence of both NADH and 2-oxoglutarate at the urea concentration 1.0 to 2.0 M the hexamer dissociated to the conformationally stable immobilized trimer possessing 60% catalytic activity of the hexamer. Studies of regulatory properties of the immobilized trimer showed that the allosteric inhibition of glutamate dehydrogenase by GTP was realized on the level of trimers, where the subunits interact through identical heterological contacts.
Karabashian
L V
LV
Agadzhanian
S A
SA
Danoian
K V
KV
Kazarian
R A
RA
D000494:Allosteric Regulation; D005969:Glutamate Dehydrogenase / Q000037:antagonists & inhibitors*; D007656:Ketoglutaric Acids / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D009243:NAD / Q000378:metabolism*; D013379:Substrate Specificity; D014508:Urea / Q000494:pharmacology*
D007656:Ketoglutaric Acids; D046911:Macromolecular Substances; D009243:NAD; D014508:Urea; D005969:Glutamate Dehydrogenase
Strukturnaia organizatsiia geksamera glutamatdegidrogenazy. 3. Vliianie kofermenta i substrata na indutsiruemye mochevinoĭ dissotsiatsiiu i inaktivatsiiu geksamera.