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.
Acciones bioquímicas o fisiológicas
L-glutamic dehydrogenase catalyzes the conversion of glutamate to α-ketoglutarate[1][2].
Propiedades físicas
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)
Definición de unidad
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.
Forma física
Solution in 50 mM Tris HCl, pH 7.8, 5 mM Na2EDTA containing 0.05% sodium azide
Otras notas
Note: Do not confuse with non-specific L-GLDH, EC 1.4.1.3.
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
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 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
Annals of clinical biochemistry, 47(Pt 1), 81-83 (2009-11-27)
Enzymatic assays using glutamate dehydrogenase (GLDH) to monitor the transformation of NAD(P)H to NAD(P)(+) by a spectrophotometric technique are the most common methods to measure plasma ammonia (PA) in routine laboratories worldwide. However, these assays can potentially be subject 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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