S A Agadzhanian

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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(More)
It was shown that the blockage of epsilon-amino group of Lis-126 residue by 2,2,6,6-tetramethyl-4-oxo-piperidine-1-oxyl (TMPO) leads to the cooperative inactivation of glutamate dehydrogenase (L-glutamate-NAD(P)-oxidoreductase, EC 1.4.1.3). The data concerning cooperative inactivation of the enzyme are interpreted by the model of hexamer with identical(More)
The effects of bivalent copper ions on the activity of bovine liver glutamate dehydrogenase (L-glutamate NAD (P) oxidoreductase, EC 1.4.1.3) were studied. Cu2+ effectively interacts with the enzyme; this interaction is accompanied by a loss of the enzyme activity in the reaction of reductive amination of alpha-ketoglutarate. The data obtained are indicative(More)
It has been shown that 2,2,6,6-tetramethyl-4-oxo-piperidine-1-oxyl selectively blocks epsilon-amino group of Lys126 residue in bovine liver glutamate dehydrogenase (L-glutamate NAD(P) oxydoreductase, EC 1.4.1.3). Modification of this residue in one of the six promoters of catalytically active hexamer is accompanied by the loss of about half of the enzymatic(More)
A procedure for purification of glutamate dehydrogenase (GDH; L-glutamate NAD(P) oxidoreductase, EC 1.4.1.3) from beef brain has been developed. The enzyme preparation obtained has the specific activity of 6.7 units per mg of protein (192-fold enhance with a 30% yield of total activity of the homogenate). In some of its physico-chemical properties (pH(More)
The character of allosteric inhibition of glutamate dehydrogenase by GTP was studied. The derivative of the enzyme not capable of being polymerized was taken as a model. It was shown that: in the absence of NADH every protomer of this derivative can bind one molecule of GTP; in the presence of NADH the additional binding site for GTP was induced; the(More)
The catalytic and regulator properties of glutamate dehydrogenase by modification of Lys-126 residue by puridoxal-5'-phosphate was studied. The phosphopyridoxyl derivative of the enzyme with blocked NADH-induced binding site of GTP not capable of being polymerized was taken as a model. It was shown that: blocking the epsilon-amino group of Lys-126 residue(More)
When modified by 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (TMPO) bovine liver glutamate dehydrogenase (L-glutamate NAD(P) oxidoreductase, E. C. 1.4.1.3) looses its catalytical activity and sensitivity to allosteric inhibitor GTP. The stoicheiometry of the binding of TMPO to glutamate dehydrogenase has been studied--each protomer bound one molecule of(More)
The urea-induced inactivation and dissociation of catalytically active hexamer of glutamate dehydrogenase (L-glutamate-NAD(P)-oxidoreductase, EC 1.4.1.3) from bovine liver were studied using radioactive phosphopyridoxyl derivative of the enzyme immobilized on cyanogen bromide-activated Sepharose CL-4B. It is shown that at neutral pH (7.0-7.8) urea causes(More)
Bovine liver glutamate dehydrogenase (L-glutamate-NAD(P)-oxidoreductase, EC 1.4.1.3) and its radioactive phosphopyridoxyl derivative were covalently immobilized on Sepharose CL-4B with different degrees of cyanogen bromide activation. The catalytical and regulatory properties of the immobilized samples of the enzymes were studied. It was shown that the(More)
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