| Gene/locus | Protein name | EC numbers | Domains | Primary reactions | Pathway role | Key experimental evidence in *P. putida* KT2440 | Evidence of regulation | Applications | Key quantitative data | Primary source (year, URL) |
|---|---|---|---|---|---|---|---|---|---|---|
| **pheA / PP_1769 / UniProt Q88M06** | Bifunctional chorismate mutase/prephenate dehydratase (“P-protein”) | **EC 5.4.99.5** (chorismate mutase); **EC 4.2.1.51** (prephenate dehydratase) | N-terminal chorismate mutase (CM) catalytic region; prephenate dehydratase (PDT) catalytic region; C-terminal ACT-like regulatory domain inferred from family/domain architecture and bacterial PheA literature | **Chorismate → prephenate** (CM step); **prephenate → phenylpyruvate + H2O + CO2** (PDT step), committing flux toward phenylalanine biosynthesis (pqac-00000006, pqac-00000009) | Branch-point enzyme at the chorismate node directing carbon from the shikimate pathway into the phenylalanine branch; competes with other chorismate-consuming pathways | Mini-Tn5 insertions in **PP_1769** caused **phenylalanine auxotrophy**; growth restored by phenylalanine but not tyrosine. RT-PCR showed **serC–pheA–PP1770/tyrA** operon linkage; PP_1769 overlaps **serC** by 6 nt and lies 61 nt from **PP1770**. Deletion of **pheA** in KT2440 was also used to redirect chorismate flux in engineering studies (pqac-00000003, pqac-00000004, pqac-00000005) | Canonical bacterial PheA enzymes are allosterically **feedback-inhibited by L-phenylalanine**, mediated by a separable C-terminal regulatory region/ACT-like domain; Phe strongly inhibits PDT activity and alters oligomerization in model bacterial PheA proteins (pqac-00000006, pqac-00000007, pqac-00000009). In *Pseudomonas*, engineered **feedback-insensitive CM/PDT (PheA) variants** were introduced to raise intracellular phenylalanine and downstream product formation (pqac-00000000) | **PHBA production:** deleting **pheA** in KT2440 removes competition for chorismate, improving precursor availability for para-hydroxybenzoic acid production. **2-Phenylethanol (2-PE):** relieving CM/PDT feedback inhibition increased phenylalanine supply and improved 2-PE production in *Pseudomonas* strains (pqac-00000001, pqac-00000002, pqac-00000000) | PHBA in engineered KT2440 reached **1.73 g/L** maximum titer and **18.1% C-mol/C-mol** carbon yield in fed-batch; strategy included **pheA deletion** (pqac-00000001, pqac-00000002). In *Pseudomonas putida* DOT-T1E derivatives, introducing a feedback-insensitive CM/PDT increased 2-PE to about **100 ppm**, with random mutagenesis pushing titers to **120 ppm** (pqac-00000000) | Molina-Henares et al., **2009**, https://doi.org/10.1111/j.1751-7915.2008.00062.x ; Yu et al., **2016**, https://doi.org/10.3389/fbioe.2016.00090 ; Godoy et al., **2024**, https://doi.org/10.1186/s13068-024-02498-1 |


*Table: This table summarizes verified functional annotation evidence for *Pseudomonas putida* KT2440 pheA/PP_1769 (UniProt Q88M06), including catalytic role, operon/genetic evidence, regulation, and engineering applications. It is useful for quickly separating direct KT2440 evidence from broader family-level regulatory inference.*