4-aminobutyrate-2-ketoglutarate transaminase

Schousboe, A., Wu, J. Y., and Roberts, E. (1973) Purification and characterization of the 4-aminobutyrate-2,ketoglutarate transaminase from mouse brain. Biochemistry 12,2868-2873. 

L-Phosphinothricin, the active ingredient of the broad-spectrum herbicide Basta (AgrEvo), can be obtained through enzymatic transamination of the corresponding oxoacid, 2-oxo-4-[(hydroxy)(methyl)phosphinoyl]butyric acid, in a coupled system with aspartate aminotransferase (AAT) and 4-aminobutyrate 2-ketoglutarate transaminase (E.C. 2.6.1.19) from E. coli (Fig. 12.7-6)[37 . In solutions containing 10% substrate, 85 % conversion was reached with only < 3 % amino acid by-products. For... 

Jung MJ, Metcalf BW. Catalytic inhibition of gamma-aminobutyric acid - alpha-ketoglutarate transaminase of bacterial origin by 4-aminohex-5-ynoic acid, a substrate analog. Biochem Biophys Res Commun 1975 67 301-306. 

This molecule specifically and irreversibly inhibits y-aminobutyrate-a-ketoglutarate transaminase. The Ki for this molecule is 2.8 ixM, some three orders of magnitude lower than the Km for the natural substrate, y-aminobutyrate. The ti/2 for inactivation of the bacterial enzyme is 9 min at 0.3 fuM gabaculine. As expected, gabaculine is not an irreversible inhibitor of the enzyme in the pyridoxamine form, and the mechanism of the irreversible inhibition by gabaculine is completely in accord with the hypothesis that enzymic conversion before inhibition. The possible mechanisms proposed for the inhibition are those in Eq. (5). ... 

Aminobutyrate-a-ketoglutarate transaminase (GABA transaminase), 33 7-Aminobutyric acid, 33,163 n-3-Amino-3-carboxypropane sulfonamide, 415, 419... 

This enzyme [EC 2.6.1.21], also known as D-aspartate aminotransferase, D-amino acid aminotransferase, and D-amino acid transaminase, catalyzes the reversible pyridoxal-phosphate-dependent reaction of D-alanine with a-ketoglutarate to yield pyruvate and D-glutamate. The enzyme will also utilize as substrates the D-stereoisomers of leucine, aspartate, glutamate, aminobutyrate, norva-hne, and asparagine. See o-Amino Acid Aminotransferase... 

The transamination reaction represented by equation (15) involves the reversible transfer of a-amino groups. Although there are probably more enzymes catalysing this type of reaction, some transaminases catalysing w-amino group transfer have also been partially identified. For example, the a-ketoglutarate—y-aminobutyrate transaminase... 

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