|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 2-ketoarginine, 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 arginine degradation II (AST pathway)) is blocked [Yang07a].
Gene Citations: [Yang07c]
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: 22.214.171.124
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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