AruH (PA4976) is a homodimeric class I pyridoxal 5'-phosphate-dependent aminotransferase of Pseudomonas aeruginosa that catalyses the first step of the arginine transaminase (ATA) pathway of L-arginine catabolism. It transfers the alpha-amino group of L-arginine to pyruvate, giving 2-ketoarginine (5-guanidino-2-oxopentanoate) and L-alanine (EC 2.6.1.84), by a ping-pong mechanism with a pH optimum of 9. It also accepts L-lysine, L-methionine, L-leucine, ornithine and L-glutamine as amino donors. The 2-ketoarginine is then decarboxylated by AruI, encoded in the same operon. The aruHI operon is induced by L-arginine through the AruRS two-component system, and the ATA pathway serves as the second aerobic arginine utilization route alongside the arginine succinyltransferase (AST) pathway.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003824 catalytic activity | IEA GO_REF:0000002 | TOO GENERAL | Summary: Root-level catalytic activity from InterPro2GO. Reason: Entailed by the accepted GO:0047635. |
| GO:0006520 amino acid metabolic process | IEA GO_REF:0000002 | TOO GENERAL | Summary: Generic InterPro2GO process term. Reason: Entailed by the accepted GO:0006527 L-arginine catabolic process. |
| GO:0006527 L-arginine catabolic process | IDA PMID:17416668 Characterization of an arginine:pyruvate transaminase in arg... | ACCEPT | Summary: PseudoCAP IDA. The purified enzyme performs the first step of the ATA arginine catabolic pathway. Reason: AruH catalyses a step of arginine catabolism; direct participation. Supporting Evidence: PMID:17416668 High-performance liquid chromatography and mass spectrometry (MS) analyses were employed to detect the presence of the transamination products 2-ketoarginine and L-alanine, thus demonstrating the proposed biochemical reaction catalyzed by AruH |
| GO:0006527 L-arginine catabolic process | IEA GO_REF:0000041 | ACCEPT | Summary: UniPathway mapping to arginine degradation; consistent with the experimental rows. Reason: Same claim as the accepted IDA and IMP rows. Supporting Evidence: PMID:17416670 This ATase activity was abolished when an aruH knockout was introduced into the strain. |
| GO:0006527 L-arginine catabolic process | IMP PMID:17416670 Functional genomics enables identification of genes of the a... | ACCEPT | Summary: UniProt IMP. aruH knockout abolishes the arginine-inducible transaminase activity and arginine growth in an aruF (AST-pathway) mutant. Reason: Genetic evidence matching the biochemistry; AruH performs a pathway step. Supporting Evidence: PMID:17416670 This ATase activity was abolished when an aruH knockout was introduced into the strain. |
| GO:0008483 transaminase activity | IBA GO_REF:0000033 | TOO GENERAL | Summary: IBA from PTN002482828, seeded by AruH itself (expected self-seed) and Synechocystis AspC Q55128, which has EXP aspartate transaminase evidence. The generic node term suits a clade spanning arginine:pyruvate and aspartate transaminases, and the IBD stands without the AruH seed. Reason: True, but the accepted GO:0047635 (is_a GO:0140385 is_a GO:0008483) entails it. The node placement is not disputed. |
| GO:0008483 transaminase activity | IDA PMID:17416668 Characterization of an arginine:pyruvate transaminase in arg... | TOO GENERAL | Summary: PseudoCAP (and UniProt) IDA and a seed of PTN002482828. Purified AruH transaminates L-arginine with pyruvate; products identified by HPLC and MS. Reason: Seed verdict SOUND, but the specific reaction is captured by GO:0047635 (RHEA:13833 is a narrowMatch xref of that term), which this review accepts. As a seed the generic term remains valid evidence for the node. Supporting Evidence: PMID:17416668 High-performance liquid chromatography and mass spectrometry (MS) analyses were employed to detect the presence of the transamination products 2-ketoarginine and L-alanine, thus demonstrating the proposed biochemical reaction catalyzed by AruH |
| GO:0008483 transaminase activity | IEA GO_REF:0000120 | TOO GENERAL | Summary: Combined IEA for transaminase activity. Reason: Entailed by the accepted GO:0047635. |
| GO:0030170 pyridoxal phosphate binding | IDA PMID:17416668 Characterization of an arginine:pyruvate transaminase in arg... | KEEP AS NON CORE | Summary: UniProt IDA; UniProt records PLP as the cofactor from this paper. PLP is the covalently bound cofactor of class I aminotransferases. Reason: True cofactor binding, ancillary to the transaminase activity. Supporting Evidence: file:PSEAE/aruH/aruH-uniprot.txt Name=pyridoxal 5'-phosphate; Xref=ChEBI:CHEBI:597326; Evidence={ECO:0000269|PubMed:17416668} |
| GO:0030170 pyridoxal phosphate binding | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: InterPro2GO PLP binding; consistent with the IDA. Reason: Same claim as the IDA row. Supporting Evidence: file:PSEAE/aruH/aruH-uniprot.txt Name=pyridoxal 5'-phosphate; Xref=ChEBI:CHEBI:597326; Evidence={ECO:0000269|PubMed:17416668} |
| GO:0047635 L-alanine:oxo-acid transaminase activity | IEA GO_REF:0000116 | ACCEPT | Summary: Rhea-based IEA. RHEA:13833 (L-arginine + pyruvate = 5-guanidino-2-oxopentanoate + L-alanine) is the experimentally demonstrated AruH reaction and is a narrowMatch of GO:0047635. Reason: Most specific existing GO term for the arginine:pyruvate transaminase reaction, directly supported by the purified-enzyme assay. Supporting Evidence: PMID:17416668 High-performance liquid chromatography and mass spectrometry (MS) analyses were employed to detect the presence of the transamination products 2-ketoarginine and L-alanine, thus demonstrating the proposed biochemical reaction catalyzed by AruH |
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Download this section (compressed HTML)Q: Should GO have an arginine:pyruvate transaminase (EC 2.6.1.84) term under GO:0047635, given that RHEA:13833 is currently only a narrowMatch of the broader alanine:oxo-acid transaminase term?
Q: Does AruH contribute to lysine catabolism in vivo, given that L-lysine is its second-best amino donor?
Experiment: Test growth of aruH and aruF aruH mutants on L-lysine and L-methionine as sole carbon or nitrogen sources to judge whether the broad donor range is physiological.
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