Enzyme glutamate dehydrogenase

Abass and colleagues developed an amperometric biosensor for NHA that uses the enzyme glutamate dehydrogenase to catalyze the following reaction. 

The enzymes glutamate dehydrogenase, glutamine synthetase, and aminotransferases occupy central positions in amino acid biosynthesis. The combined effect of... 

McKenna,M. C.,Stevenson,J. H.,Huang,X. etal. Differential distribution of the enzymes glutamate dehydrogenase and aspartate aminotransferase in cortical synaptic mitochondria contributes to metabolic compartmentation in cortical synaptic terminals. Neurochem. Int. 37 229-241, 2000. 

Very low concentrations of substrates may be assayed by recycling the test substrate for an appreciable but definite period of time and measuring the amount of product formed. The coenzyme NADPH, for instance, may be assayed using the two enzymes glutamate dehydrogenase (EC 1.4.1.3) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) ... 

The amino acid glutamate is deaminated in a reaction catalysed by the enzyme glutamate dehydrogenase, using either NAD+ or NADF as the oxidising agent, as follows ... 

The ammonia can then be utilised for amino acid synthesis in some or all of the microorganisms in the intestine, a process requiring the enzyme glutamate dehydrogenase to incorporate the ammonia into glutamate... 

Several explanations centre on the enzyme glutamate dehydrogenase, which is assumed to catalyse a nearequilibrium reaction in brain mitochondria ... 

Scheme 4.10 shows the equilibrium for the enzyme glutamate dehydrogenase. Based on the name of the enzyme alone, would you expect this enzyme to drive the reaction to the left or right Based on the Km values, does your answer change Note that the position of the equilibrium for this reaction is not determined by Km values but the free energy difference between the products and starting materials. 

Ammonia is normally condensed with 2-oxoglutarate and thus converted to glutamate via the enzyme glutamate dehydrogenase this enzyme is of highest activity in the liver and kidney. Glutamate is produced from 2-oxoglutarate and ammonia as follows ... 

B) the enzyme glutamate dehydrogenase catalyzes the fixation of ammonia—the addition of ammonia to an organic compound... 

For net removal of amino nitrogen, a second enzymatic reaction must take place that removes the amino group from Glu for disposal. The net removal of the amino nitrogen is accomplished by the mitochondrial enzyme glutamate dehydrogenase (GDH), which catalyzes the oxidative deamination of Glu to a-KG in a reaction that uses NAD+ as the electron acceptor. The enzyme can... 

Z63 Write a balanced equation for the synthesis of glutamate that is mediated by the enzyme glutamate dehydrogenase. 

The reactions of amino compounds, considered so far, have been largely concerned with the production of essential cell constituents firom ingested material. The remaining section is concerned with those reactions by which excess amino compounds are converted first to ammonia and then to common excretion products. The division between biosynthetic and degradative reactions is not clear cut as can be seen from the fact that the reaction catalysed by the enzyme glutamic dehydrogenase produces ammonia and has already been discussed in sections II and IV.B. Oxidative deamination of the D-amino acids has also been discussed (section V.A) because the reverse of this reaction appears to be the main route by which o-amino acids are formed in microorganisms but it is also believed to be the... 

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