This enzyme is useful for enzymatic determination of NH3, α-ketoglutaric acid and L-glutamic acid, and for assay of leucine aminopeptidase and urease. This enzyme is also used for enzymatic determination of urea when coupled with urease (URH-201) in clinical analysis. In vitro, various activity assays of this enzyme examine the conversion of α-ketoglutarate to L-glutamate, in the presence of excess ammonium ions (NH4+) and NADPH.
Biochem/physiol Actions
L-glutamic dehydrogenase catalyzes the conversion of glutamate to α-ketoglutarate[1][2].
Physical properties
Isoelectric point : 4.6 Michaelis constants : 1.1 X 10-3M (NH3), 3.4 X 10-4M (α-Ketoglutarate) 1.2 X 10-3M (L-Glutamate), 1.4 X 10-5M (NADPH), 1.5 X 10-5M (NADP+) Structure : 6 subunits (M.W.50,000) per mol of enzyme Inhibitors : Hg++, Cd++, p-chloromercuribenzoate, pyridine, 4-4′-dithiopyridine, 2,2′-dithiopyridine Optimum pH : 8.5 (α-KG→L-Glu) 9.8 (L-Glu→α-KG) Optimum temperature : 45oC(α-KG−L-Glu) 45-55oC (L-Glu→α-KG) pH stability : pH 6.0 - 8.5 (25oC, 20hr) Thermal stability : below 50oC (pH 7.4, 10min)
Unit Definition
One unit will reduce 1.0 μmole of α-ketoglutarate to L-glutamate per min at pH 8.3 at 30 °C in the presence of ammonium ions and NADPH.
Physical form
Solution in 50 mM Tris HCl, pH 7.8, 5 mM Na2EDTA containing 0.05% sodium azide
Other Notes
Note: Do not confuse with non-specific L-GLDH, EC 1.4.1.3.
The Biochemical journal, 223(1), 161-168 (1984-10-01)
In steady-state kinetic studies of ox liver glutamate dehydrogenase in 0.11 M-potassium phosphate buffer, pH7, at 25 degrees C, the concentration of ADP was varied from 0.5 to 1000 microM. Inhibition was observed except when the concentrations of both glutamate
Excessive ammonium blood concentration causes many serious neurological complications. The medications currently used are not very effective. To remove ammonium from the blood, erythrocyte-bioreactors containing enzymes that processing ammonium have been proposed. The most promising bioreactor contained co-encapsulated glutamate dehydrogenase
The Journal of biological chemistry, 257(10), 5579-5583 (1982-05-25)
The activity of bovine liver glutamate dehydrogenase is affected in several ways depending on substrate concentrations and pH. At ph 6.5 and below, both oxidative deamination and reductive amination reactions are inhibited by ADP. At pH 7.0 and above both
Delta(1)-Pyrroline-5-carboxylate dehydrogenase (P5CDh) is known to preferentially use NAD(+) as a coenzyme. The k(cat) value of Thermus thermophilus P5CDh (TtP5CDh) is four times lower for NADP(+) than for NAD(+). The crystal structure of NADP(+)-bound TtP5CDh was solved in order to
Acinetobacter lwoffii strain ISP4 metabolizes isophthalate rapidly compared with Pseudomonas aeruginosa strain PP4 and Pseudomonas strain PPD. Isophthalate has been reported to be a potent competitive inhibitor of glutamate dehydrogenase (GDH). Exogenous supplementation of isophthalate with glutamate or alpha-ketoglutarate at
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