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MetaCyc Enzyme: arginine-α-ketoglutarate transaminase

Species: Pimelobacter simplex

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

Summary:
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 2-ketoarginine. Catabolite repression of enzyme formation was observed upon addtion of β-D-glucose 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: ?


Enzymatic reaction of: arginine-α-ketoglutarate transaminase

L-arginine + 2-oxoglutarate <=> L-glutamate + 2-ketoarginine

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, 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: 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]
2-ketoarginine
300.0
[Tachiki80]

pH(opt): 8-8.5 [Tachiki80]


References

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


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Fri Nov 28, 2014, biocyc13.