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Transamination is a chemical reaction that transfers an amino group to a ketoacid to form new amino acids.This pathway is responsible for the deamination of most amino acids. This is one of the major degradation pathways which convert essential amino acids to non-essential amino acids (amino acids that can be synthesized de novo by the organism).
"Ketoglutaric acid" and "ketoglutarate", when not qualified as α or β, almost always refers respectively to α-ketoglutaric acid or α-ketoglutarate. [2] α-Ketoglutarate is an intermediate in the citric acid cycle, a cycle that supplies the energy to cells. [2] It is also an intermediate in or product of several other metabolic pathways.
2. Glutamate can be excreted or can be further metabolized to α-ketoglutarate. For the conversion of glutamate to α-ketoglutarate three different reactions are possible: Catalyzing enzymes: glutamate dehydrogenase (GlDH), EC 1.4.1.2; glutamate pyruvate transaminase (GPT), also called alanine transaminase (ALT), EC 2.6.1.2
The alanine amino acid acts as a shuttle - it leaves the cell, entering the blood stream and traveling to hepatocytes in the liver, where essentially this entire process is reversed. Alanine undergoes a transamination reaction with free α-ketoglutarate to yield glutamate, which is then deaminated to form pyruvate and, ultimately, free ammonium ...
Alanine is produced by the transamination of one molecule of pyruvate using two alternate steps: 1) conversion of glutamate to α-ketoglutarate using a glutamate-alanine transaminase, and 2) conversion of valine to α-ketoisovalerate via Transaminase C. Not much is known about the regulation of alanine synthesis.
Enzyme-bound pyridoxamine in turn reacts with pyruvate, oxaloacetate, or alpha-ketoglutarate, giving alanine, aspartic acid, or glutamic acid, respectively. Many transamination reactions occur in tissues, catalysed by transaminases specific for a particular amino/keto acid pair.
Alpha-ketoglutarate participates in cell signaling by functioning as a coenzyme. [6] It is commonly used in transamination reactions. Beta-keto acids, beta-ketoacids, or 3-oxoacids, such as acetoacetic acid, have the ketone group at the second carbon from the carboxylic acid. They generally form by the Claisen condensation.
This reaction generates α-ketoglutarate (α-KG) and ammonia. Glutamate can then be regenerated from α-KG via the action of transaminases or aminotransferase, which catalyze the transfer of an amino group from an amino acid to an α-keto acid. In this manner, an amino acid can transfer its amine group to glutamate, after which GDH can then ...