Catalytic reaction and detection principle of glutamate dehydrogenase GLDH
Glutamate dehydrogenase GLDH (Glutamate Dehydrogenase) or GDH is an enzyme related to amino acid metabolism in the body. It exists in liver, brain, and kidney tissues and is usually used as a detection indicator for liver diseases. GLDH can catalyze the dehydrogenation of L-glutamic acid to α-ketoglutarate and enter the tricarboxylic acid cycle.
Glutamic acid is an acidic amino acid with two carboxyl groups in its molecule. Its chemical name is α-aminoglutarate. It occupies an important position in protein metabolism in organisms and participates in many important chemical reactions in animals, plants and microorganisms. . Glutamic acid (2-aminoglutaric acid) has three isomers, left, right and racemate. L-glutamic acid is its L-glutamate, and glutamate dehydrogenase can dehydrogenate (oxidative deamination) is L-glutamic acid.
The catalytic principle and detection of glutamate dehydrogenase
Glutamate dehydrogenase mainly exists in the mitochondria of liver, myocardium and kidney cells, and a small amount exists in the mitochondria of brain, skeletal muscle and white blood cells. In addition to catalyzing the dehydrogenation of L-glutamic acid and its reversible reaction, it also has the function of catalyzing other amino acids, such as catalyzing and oxidizing the deamination of L-valine, L-2-aminobutyric acid and L-leucine.
Detection principle of glutamate dehydrogenase GDH:
The activity detection principle of the finished product of glutamate dehydrogenase GLDH reaction equation α-ketoglutarate α-Ketoglutarate + NH3 + NADH + H + Under the catalysis of glutamate dehydrogenase, glutamate GLDH + NAD + +H2O NADH is generated. Reagents: A 0.1 M Tris-HCl buffer, pH 8.3 B 1.5M NH4Cl solution C 0.225M α-ketoglutarate solution (pH 7.0-9.0) D 7.5mM NADH solution E Enzyme diluent: 0.1 M Tris-HCl buffer Liquid, pH 8.3. The consumption of NADH can be detected by light absorption at 340nm. Measurement time: 180s Delay time: 60s Integration time: 120s Coefficient/factor: 6.776 Measurement temperature: 30±1℃ 3.2 Sample preparation If the sample to be tested is solid, it can be dissolved at the ratio of 10mg sample/1000ul ultrapure water. After dissolution, place at 2-8 degrees.
Glutamate dehydrogenase is a very important enzyme in the liver, involved in the metabolism of glutamate, α-ketoglutarate and other amino acids, so the detection of serum GDH content is an important indicator of health. The GDH enzyme preparation provided by Desheng is the raw material of the kit, which is mainly used for biochemical testing and related research experiments.
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