| Topic | Key finding | Evidence/quantitative details | Primary source (with year) | URL |
|---|---|---|---|---|
| Gene identity in *P. putida* KT2440 | **tpiA** maps to **PP_4715** and encodes triose phosphate isomerase (TpiA) | Study explicitly annotates **tpiA (PP4715, triose phosphate isomerase)** among KT2440 mutants tested (pqac-00000000, pqac-00000012) | Nikel et al., *J. Biol. Chem.* (2015) | https://doi.org/10.1074/jbc.M115.687749 |
| Primary biochemical function | TIM/TPI catalyzes reversible isomerization of **DHAP ⇄ D-GAP/G3P** | Conserved glycolytic reaction; stereospecific conversion of DHAP to D-GAP; no cofactor or metal required (pqac-00000008) | Wierenga et al., *Cell. Mol. Life Sci.* (2010) | https://doi.org/10.1007/s00018-010-0473-9 |
| Catalytic mechanism / residues | Catalysis uses conserved active-site residues, with glutamate as catalytic base | Residues identified as **Asn11, Lys13, His95, Glu167**; proton-shuttling via enediolate intermediate; loop-6/loop-7 closure helps shield active site (pqac-00000002, pqac-00000008) | Wierenga et al., *Cell. Mol. Life Sci.* (2010) | https://doi.org/10.1007/s00018-010-0473-9 |
| Alternative residue numbering in eukaryotic review | Same catalytic core appears in alternate numbering scheme | Myers review lists active-site residues as **K14, H96, E166** in eukaryotic TPI context, consistent with highly conserved catalytic core (pqac-00000003) | Myers & Palladino, *Molecular Medicine* (2023) | https://doi.org/10.1186/s10020-023-00612-x |
| Enzyme efficiency | TIM is a near-diffusion-limited catalyst | Reported **kcat/Km ≈ 1 × 10^9 M^-1 s^-1** (D-GAP→DHAP direction); **kcat ~500 s^-1** for DHAP→D-GAP and **~5,000 s^-1** for D-GAP→DHAP; **Km ~1.2 mM (DHAP)** and **~0.25 mM (D-GAP)** (pqac-00000002, pqac-00000008) | Wierenga et al., *Cell. Mol. Life Sci.* (2010) | https://doi.org/10.1007/s00018-010-0473-9 |
| Oligomeric state / structural requirement | TIM is functionally dimeric, and dimerization supports full activity | Review states **only the TIM dimer is fully active**; monomeric TIM variants show about **kcat ≈ 1 s^-1** and **Km ≈ 5 mM**, roughly **1,000-fold lower kcat** and **10-fold higher Km** than wild type (pqac-00000005) | Wierenga et al., *Cell. Mol. Life Sci.* (2010) | https://doi.org/10.1007/s00018-010-0473-9 |
| Subcellular localization | TIM is generally a **cytosolic** glycolytic enzyme | Review notes TIM is generally cytosolic in most organisms, with special compartmentalization exceptions outside typical bacteria (pqac-00000002, pqac-00000004) | Wierenga et al., *Cell. Mol. Life Sci.* (2010) | https://doi.org/10.1007/s00018-010-0473-9 |
| Essentiality / conservation | TPI is a highly conserved, essential glycolytic enzyme | Myers review describes TPI as **essential** and **highly conserved**, required for DHAP catabolism and net ATP yield from anaerobic glucose metabolism (pqac-00000003) | Myers & Palladino, *Molecular Medicine* (2023) | https://doi.org/10.1186/s10020-023-00612-x |
| KT2440 mutant phenotype | **tpiA** disruption causes severe growth defect in KT2440 | Authors report **“lack of growth of a tpiA mutant in either glucose or succinate”**, indicating an unexpectedly strong requirement under both glycolytic and gluconeogenic conditions tested (pqac-00000001, pqac-00000011) | Nikel et al., *J. Biol. Chem.* (2015) | https://doi.org/10.1074/jbc.M115.687749 |
| Pathway context in KT2440 | TpiA participates in the partial EMP arm embedded within ED/PP-centered metabolism | In KT2440, ED pathway is essential for glucose growth, PP contribution is described as negligible in that condition, yet **partial EMP route is remarkably relevant**; TpiA is called a key EMP step despite lack of canonical phosphofructokinase (pqac-00000011, pqac-00000012) | Nikel et al., *J. Biol. Chem.* (2015) | https://doi.org/10.1074/jbc.M115.687749 |
| Enzyme activity in KT2440 extracts | TpiA activity is present under both glycolytic and gluconeogenic growth | **Fbp, Fda, and TpiA were equally active in both glucose and succinate cultures**; measured intracellular **G3P concentration = 140 µM** for quasi in vivo assays (pqac-00000010) | Nikel et al., *J. Biol. Chem.* (2015) | https://doi.org/10.1074/jbc.M115.687749 |
| Glucose flux context in KT2440 | Upper central metabolism is dominated by ED/periplasmic oxidation, but triose-phosphate balancing remains important | Reported values include lag phase **1.2 ± 0.5 h**, gluconate yield **0.34 ± 0.02 C-mol/C-mol**, 2-KG yield **0.11 ± 0.01 C-mol/C-mol**, **>80%** of glucose influx via periplasmic oxidation, **~25%** of F6P formed through PP pathway, and **~50%** relative ED contribution to pyruvate formation (pqac-00000011) | Nikel et al., *J. Biol. Chem.* (2015) | https://doi.org/10.1074/jbc.M115.687749 |
| Moonlighting caution | Non-glycolytic “moonlighting” roles are described for eukaryotic TPI, not established here for *P. putida* tpiA | 2023 review highlights nuclear TPI roles in eukaryotes and stress/chemotherapy-linked nuclear localization; these findings should not be over-transferred to bacterial KT2440 annotation (pqac-00000003, pqac-00000009) | Myers & Palladino, *Molecular Medicine* (2023) | https://doi.org/10.1186/s10020-023-00612-x |


*Table: This table compiles validated organism-specific facts for *Pseudomonas putida* KT2440 tpiA/PP_4715 together with core triosephosphate isomerase biochemistry. It is useful as a compact evidence map for function, pathway role, localization, and key quantitative properties.*