Amino acid degradation glutamate oxidative deamination

In general, amino acid degradation begins with deamination. Most deamination is accomplished by transamination reactions, which are followed by oxidative deaminations that produce ammonia. Although most deaminations are catalyzed by glutamate dehydrogenase, other enzymes also contribute to ammonia formation. Ammonia is prepared for excretion by the enzymes of the urea cycle. Aspartate and CO, also contribute atoms to urea. 

Most of the ammonia generated in amino acid degradation is produced by the oxidative deamination of glutamate. Additional ammonia is produced in several other reactions catalyzed by the following enzymes ... 

The first stage in the oxidative degradation of amino acids is the removal of the amino group by one of two main pathways, oxidative deamination or transamination. In transamination the amino group is transferred to the a-carbon atom of a keto acid, usually a-ketogjutarate, resulting in the production of another keto acid and glutamate. The reactions are catalysed by enzymes known as aminotransferases. The reaction for aspartate may be represented as ... 

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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