MetaCyc Enzyme: arginine-α-ketoglutarate transaminase

Species: Pimelobacter simplex

Subunit composition of arginine-α-ketoglutarate transaminase = [arginine-α-ketoglutarate transaminase subunit]

arginine-α-ketoglutarate transaminase was purified from Pimelobacter simplex grown on L-arginine as a carbon source. Synthesis of the enzyme was inducible by either L-arginine or 5-guanidino-2-oxo-pentanoate. Catabolite repression of enzyme formation was observed upon addtion of β-D-glucopyranose or glycerol to the media.

The enzyme required a pyridoxal 5'-phosphate cofactor, and demonstrated activity with alternative substrates. Activity with N-nitro-L-arginine, L-citrulline and L-alanine was 22.5, 15.8 and 9.5% of the activity with L-arginine, respectively. The enzyme could also use pyruvate instead of 2-oxoglutarate, with 12% of the activity [Tachiki80].

Molecular Weight of Multimer: 110 kD (experimental) [Tachiki80]

Gene-Reaction Schematic

Gene-Reaction Schematic

Enzymatic reaction of: arginine-α-ketoglutarate transaminase

Inferred from experiment

EC Number: 2.6.1.-

L-arginine + 2-oxoglutarate ⇄ L-glutamate + 5-guanidino-2-oxo-pentanoate

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction of enzyme catalysis.

This reaction is reversible.

Alternative Substrates for 2-oxoglutarate: pyruvate [Tachiki80]
Alternative Substrates for L-arginine: L-alanine [Tachiki80], L-citrulline [Tachiki80], N-nitro-L-arginine [Tachiki80]

In Pathways: L-arginine degradation XI

Cofactors or Prosthetic Groups: pyridoxal 5'-phosphate [Tachiki80]

Inhibitors (Unknown Mechanism): Hg2+ [Tachiki80], phenylhydrazine [Tachiki80], p-chloromercuribenzoate [Tachiki80]Kinetic Parameters:
Substrate Km (μM) Citations
2-oxoglutarate 8100.0 [Tachiki80]
L-arginine 2900.0 [Tachiki80]
L-glutamate 25000.0 [Tachiki80]
5-guanidino-2-oxo-pentanoate 300.0 [Tachiki80]

pH(opt): 8-8.5 [Tachiki80]


Tachiki80: Tachiki T, Kohno H, Sugiyama K, Matsubara T, Tochikura T (1980). "Purification, properties and formation of arginine-alpha-ketoglutarate transaminase in Arthrobacter simplex." Biochim Biophys Acta 615(1);79-84. PMID: 7426667

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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