Exchange-transamination

Without additional reagents Reactions of cupric inner complex salts Ligand exchange Transamination... 

Transamination (Section 29.9) The exchange of an amino group and a keto group between reactants. 

Glutamate can then participate in the formation of other amino acids via the process called transamination. Transamination is the exchange of the amino group from an amino acid to a keto acid, and provides the most common process for the introduction of nitrogen into amino acids, and for the removal of nitrogen from them. The reaction is catalysed by a transaminase enzyme, and the coenzyme pyridoxal phosphate (PLP) is required. 

Transamination, often also referred to as aminotransfer, is applied to those enzymatic reactions in which an amino group is exchanged between an amino acid and an a-keto acid. This type of reaction is catalyzed by a group of transferases called transaminases or aminotransferases. They are active in both the cytosol and the mitochondria of most cells. An essential prosthetic group of such enzymes is pyridoxal phosphate, and the reaction is generally of the ping-pong type. 

For two transaminases the remaining unknown stereochemical parameter was determined by demonstrating an internal transfer of tritium (dialkyl amino acid transaminase) [28] or deuterium (pyridoxamine-pyruvate transaminase) [27] from the a-position of the substrate L-alanine to C-4 of the cofactor. Internal hydrogen transfer from the a-position of the substrate amino acid to C-4 of PLP has also been demonstrated for two of the abortive transamination reactions, those catalyzed by tryptophan synthase fi2 protein [32] and by aspartate-/8-decarboxylase [31]. In addition, the same phenomenon must occur in alanine transaminase, as deduced from the observation that the enzyme catalyzes exchange of the /8-hydrogens of... 

Position leucine and a-ketoglutarate so that the groups to be exchanged are aligned. This arrangement makes it easy to predict the products of transamination reactions. 

Transamination, a type of protonic-acid cleavage, yields amine upon exchange with the amide moiety of a nonmetal or metal amide. These reactions are used to prepare amides or imides. The amine formed is of incidental interest, e.g. ... 

We saw in Section 29.6 that the fir.st step in the metabolism of most amino acids is transamination, a process in which the amino group of the amino acid exchanges with the keto group of a-ketoglutarate. Reaction of the amino acid with pyridoxal... 

Dialyze transaminated DNA against four exchanges of 5 mM sodium phosphate (pH 7.5). Exchange to 0.1 M sodium carbonate buffer (pH 9.8) containing 0.1 mM EDTA (note that ethanol precipitation results in precipitation of phosphates). 

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