|Gene:||aruH||Accession Number: G-10354 (MetaCyc)|
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
Enzymatic reaction of: L-arginine:pyruvate transaminase
EC Number: 220.127.116.11
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.
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].
T(opt): 42 °C [Yang07a]
pH(opt): 9 [Yang07a]
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