Description
Glutamate dehydrogenase (GLDH) is an enzyme, present in most microbes and the mitochondria of eukaryotes, as are some of the other enzymes required for urea synthesis, that converts glutamate to α-ketoglutarate, and vice versa. In animals, the produced ammonia is usually used as a substrate in the urea cycle. Typically, the α-ketoglutarate to glutamate reaction does not occur in mammals, as glutamate dehydrogenase equilibrium favours the production of ammonia and α-ketoglutarate.
Abbr
GLDH (NAD) (Microorganism)
Applications
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 in clinical analysis.
Appearance
White amorphous powder, lyophilized
Enzyme Commission Number
EC 1.4.1.2
Activity
GradeⅡ 100 U/mg-solid or more
Contaminants
NAD oxidase < 1.0×10⁻²%
Molecular Weight
approx. 260 kDa
pH Stability
pH 5.0-10.0 (25°C, 20hr)
Michaelis Constant
9.21×10⁻³M (NH₃), 4.80×10⁻³M (α-Ketoglutarate), 7.8×10⁻⁵M (L-Glutamate), 1.29×10⁻⁴M (NADH), 5.89×10⁻⁴M (NAD⁺)
Structure
6 subunits per mol of enzyme
Optimum pH
7.5-8.0 (α-KG→L-Glu) 9.0 (L-Glu→α-KG)
Optimum temperature
55°C (α-KG→L-Glu) 50°C (L-Glu→α-KG)
Thermal stability
below 50°C (pH 8.3, 10min)
Stability
Stable at-20°C for at least one year
Inhibitors
Heavy metals, PCMB, IAA
Synonyms
Glutamate Dehydrogenase; glutamic dehydrogenase; glutamate dehydrogenase (NAD); glutamate oxidoreductase; glutamic acid dehydrogenase; L-glutamate dehydrogenase; NAD-dependent glutamate dehydrogenase; NAD-dependent glutamic dehydrogenase; NAD-glutamate dehydrogenase; NAD-linked glutamate dehydrogenase; NAD-linked glutamic dehydrogenase; NAD-specific glutamic dehydrogenase; NAD-specific glutamate dehydrogenase; NAD: glutamate oxidoreductase; NADH-linked glutamate dehydrogenase; L-glutamate: NAD+ oxidoreductase (deaminating); EC 1.4.1.2; GLDH