MetaCyc Enzyme: L-arginine:pyruvate transaminase

Gene: aruH Accession Number: G-10354 (MetaCyc)

Synonyms: PA4976

Species: Pseudomonas aeruginosa

Subunit composition of L-arginine:pyruvate transaminase = [AruH]2
         L-arginine:pyruvate transaminase subunit = AruH

The aruH gene of Pseudomonas aeruginosa encodes an L-arginine:pyruvate transaminase that converts L-arginine to 5-guanidino-2-oxo-pentanoate, the key reaction in an alternative arginine degradation pathway found in this organism. The gene was cloned, and fused to a His-tag, and the protein was expressed in Escherichia coli, purified and characterized [Yang07a]. The enzyme is a homodimer of 79.3 kDa, and requires pyridoxal 5'-phosphate for activity.

The enzyme is most active with L-arginine, but can accept several other amino acids as substrate (see below). The high Km value of AruH for L-arginine (13.9 mM) may explane why this pathway is not the preferred arginine degradation pathway in Pseudomonas aeruginosa and why it is only active when the major pathway (see L-arginine degradation II (AST pathway)) is blocked [Yang07a].

Gene Citations: [Yang07b]

Molecular Weight of Polypeptide: 43.0 kD (experimental) [Yang07a ]

Molecular Weight of Multimer: 79.3 kD (experimental) [Yang07a]

Unification Links: Entrez-gene:880915

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Created 03-Dec-2007 by Caspi R , SRI International

Enzymatic reaction of: L-arginine:pyruvate transaminase

EC Number:

L-arginine + pyruvate <=> 5-guanidino-2-oxo-pentanoate + L-alanine

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

This reaction is reversible.

Alternative Substrates for L-arginine: L-lysine [Yang07a ] , L-methionine [Yang07a ] , L-leucine [Yang07a ] , L-ornithine [Yang07a ] , L-glutamine [Yang07a ]

In Pathways: L-arginine degradation IX (arginine:pyruvate transaminase pathway)

The calculated Vmax and kcat were 54.6 μmol/min/mg protein and 38.6 s-1. The apparent Km and catalytic efficiency (kcat/Km) for pyruvate were 1.6 mM and 24.1 mM-1 s-1, respectively. The apparent Km and catalytic efficiency (kcat/Km) for L-arginine were 13.9 mM and 2.8 mM-1 s-1, respectively [Yang07a].

Cofactors or Prosthetic Groups: pyridoxal 5'-phosphate [Yang07a]

Kinetic Parameters:

Km (μM)

T(opt): 42 °C [Yang07a]

pH(opt): 9 [Yang07a]


Yang07a: Yang Z, Lu CD (2007). "Characterization of an arginine:pyruvate transaminase in arginine catabolism of Pseudomonas aeruginosa PAO1." J Bacteriol 189(11);3954-9. PMID: 17416668

Yang07b: Yang Z, Lu CD (2007). "Functional genomics enables identification of genes of the arginine transaminase pathway in Pseudomonas aeruginosa." J Bacteriol 189(11);3945-53. PMID: 17416670

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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
Page generated by SRI International Pathway Tools version 19.0 on Tue Oct 13, 2015, BIOCYC11A.