pchA (PA4231, Q51508) notes
Isochorismate synthase, first and rate-limiting enzyme of salicylate/pyochelin biosynthesis; last gene of the pchDCBA operon. No deep-research provider was available; literature search by hand (cached abstracts of PMID:12624097 and PMID:7500944; QuickGO for E. coli EntC).
Literature
- Gaille, Reimmann & Haas 2003 (PMID:12624097; abstract only): PchA purified to homogeneity from P. aeruginosa ["The PchA protein was purified to apparent electrophoretic homogeneity from a PchA-overexpressing P. aeruginosa strain."]; Mg2+-dependent 52-kDa monomer; ["a K(m) = 4.5 microm and a k(cat) = 43.1 min(-1) were determined for chorismate"]; PchA level limits salicylate formation and its overexpression raises pyochelin.
- Serino et al. 1995 (PMID:7500944; abstract only): pchBA necessary for salicylate formation; complementation of an E. coli entC mutant needs pchBA; ["a pathway leading from chorismate to isochorismate and then to salicylate plus pyruvate, catalyzed consecutively by the iron-repressible PchA and PchB proteins"].
- QuickGO (2026-11-05): E. coli EntC P0AEJ2 has GO:0008909 by IDA (PMID:2139795, 2684979) and EXP (PMID:17243787, 20079748).
Review decisions
All six rows ACCEPT (activity IBA/IDA/IEA; salicylic acid biosynthetic process IDA/IEA; pyochelin biosynthetic process IDA). PchA catalyses a step of both processes, so involved_in is participation, not necessity.
PseudoCAP IBA-seed assessment
| PTN node |
node term |
n_seeds |
leaf IBAs |
seed annotation (term, evidence, PMID) |
verdict |
rationale |
other seeds |
IBD stands without this seed? |
| PTN000132907 |
GO:0008909 isochorismate synthase activity |
2 |
17 (13 taxa) |
GO:0008909, IDA, PMID:12624097 (PseudoCAP) |
SOUND |
Abstract reports purified-enzyme kinetics with chorismate for PchA itself. Node term suits an isochorismate synthase clade. |
E. coli EntC P0AEJ2 (IDA/EXP) |
Yes, on EntC |
No PSEUDOCAP or GO_CENTRAL defect.