| Aspect | Summary |
|---|---|
| identity | **Gene/protein verified as the requested target:** *Pseudomonas putida* KT2440 **pgl** = **PP_1023**, annotated as **6-phosphogluconolactonase / 6-phosphogluconate lactonase (6PGL)** in the **zwfA-pgl-eda** operon; literature context matches UniProt Q88P30 and not an unrelated pgl gene from another organism/system (pqac-00000000, pqac-00000004, pqac-00000008) |
| reaction/EC | Catalyzes the **lactonase step** between Zwf and downstream 6-phosphogluconate metabolism: Zwf generates **6-phosphogluconolactone** from glucose-6-phosphate, and **Pgl hydrolyzes this intermediate to 6-phosphogluconate**; consistent with **EC 3.1.1.31** and the enzyme name 6-phosphogluconolactonase (pqac-00000001, pqac-00000004, pqac-00000008) |
| substrate/product | **Substrate:** 6-phosphogluconolactone (the Zwf product from G6P). **Product:** 6-phosphogluconate (6PG, also denoted 6P-Gluc), the central branch-point metabolite linking ED, PPP, and EDEMP glucose catabolism in KT2440 (pqac-00000001, pqac-00000004, pqac-00000008) |
| pathway role | Pgl functions in the **cytosolic phosphorylative branch** of glucose assimilation and feeds the **6PG node**, which then predominantly enters the **Entner-Doudoroff (ED) pathway** while a smaller fraction enters the **pentose phosphate pathway (PPP)**. Reviews and flux papers place Pgl as a key upper-pathway step in the three-pronged glucose-to-6PG network of *Pseudomonas* (pqac-00000001, pqac-00000002, pqac-00000010) |
| operon context | **Operon:** **zwfA-pgl-eda**. This genomic arrangement couples the first oxidative PPP/ED step (**Zwf**), the lactonase step (**Pgl**), and KDPG aldol cleavage (**Eda**), reflecting coordinated function in upper glucose catabolism (pqac-00000000, pqac-00000008, pqac-00000005) |
| regulation | **HexR-dependent repression/derepression:** HexR is an **RpiR-family** regulator divergently transcribed from the operon and binds a consensus **TTGT-N7/8-ACAA** operator in target promoters such as **zwf**; the ED intermediate **KDPG** acts as the effector that causes HexR dissociation and transcriptional activation. In reporter assays, **ΔhexR increased PzwfA activity ~2.5-fold**, supporting repression of the operon under tested conditions (pqac-00000000, pqac-00000009, pqac-00000006) |
| localization inference | Available evidence supports **cytoplasmic/cytosolic localization** for Pgl activity: it acts in the intracellular branch where glucose imported into the cytoplasm is phosphorylated by **Glk**, oxidized by **Zwf**, and then processed by **Pgl** to 6PG. This contrasts with **periplasmic** oxidation steps catalyzed by **Gcd/Gad** upstream of alternative routes (pqac-00000001, pqac-00000008, pqac-00000011) |
| quantitative data/statistics | Recent and foundational studies provide pathway-level numbers rather than purified Pgl kinetics in KT2440: **>90%** of consumed sugar was reported to be converted to **6PG** and then **predominantly routed through ED**, with **<10%** entering PPP in one recent summary; ^13C flux analysis estimated **91% of the 6PG pool** was funneled into **ED**, while only **~14-17% of total 6PG** originated from **G6P via Zwf** under the analyzed glucose condition; another source summarized glucose uptake as roughly **~67% periplasmic oxidation** vs **~33% direct cytoplasmic transport/phosphorylation** (pqac-00000001, pqac-00000002, pqac-00000011) |
| key references w/ year and URL | **Chen et al., 2024**, *Microbial Biotechnology* — https://doi.org/10.1111/1751-7915.70059; **Volke et al., 2021**, *mSystems* — https://doi.org/10.1128/msystems.00014-21; **Udaondo et al., 2018**, *Microbial Biotechnology* — https://doi.org/10.1111/1751-7915.13263; **Nikel et al., 2015**, *J. Biol. Chem.* — https://doi.org/10.1074/jbc.M115.687749; pathway/operon schematics in Udaondo review Figures 1-3 (pqac-00000000, pqac-00000002, pqac-00000005, pqac-00000006) |


*Table: This table summarizes the verified identity, enzymatic role, pathway placement, regulation, localization inference, and quantitative pathway data for *Pseudomonas putida* KT2440 pgl (PP_1023; UniProt Q88P30). It is useful as a compact evidence-backed functional annotation reference for the gene.*