| Claim | Key quantitative details | Evidence type | Source |
|---|---|---|---|
| **Identity/function:** PP_5260 (also called **ydcJ**; tentatively named **hglS**) from *Pseudomonas putida* KT2440 is a DUF1338/HGLS-family metalloenzyme that catalyzes conversion of **2-oxoadipate (2OA)** to **D-2-hydroxyglutarate (D-2HG)** | Figure-localized kinetic/reaction panels identify PP_5260 with the 2OA→D-2HG reaction; family/domain assignment is DUF1338/HGLS-like (pqac-00000006, pqac-00000008) | RB-TnSeq-guided pathway discovery; in vitro enzymology; family/domain inference | Thompson et al., **2019-06**, mBio, DOI: 10.1128/mBio.02577-18, https://doi.org/10.1128/mbio.02577-18 (pqac-00000006, pqac-00000008) |
| **Reaction/product:** HglS directly converts **2OA** to **D-2HG** | Short-time assays showed **1:1 stoichiometry**: about **200 µM 2HG formed** with **800 µM 2OA remaining** after 5 min from a 1 mM starting substrate pool; long assays showed ~**92% decrease** in 2OA versus boiled/EDTA controls (pqac-00000000, pqac-00000004) | In vitro enzymology; substrate/product quantification | Thompson et al., **2019-06**, mBio, DOI: 10.1128/mBio.02577-18, https://doi.org/10.1128/mbio.02577-18 (pqac-00000000, pqac-00000004) |
| **Stereochemistry:** the product is specifically **D-2HG**, not L-2HG | Product identity matched **2HG standards** by LC-TOF/HPLC, and stereochemistry was assigned by an **enzyme-coupled assay specific for D-2HG** (pqac-00000000, pqac-00000004) | LC-TOF/HPLC product identification; stereospecific coupled assay | Thompson et al., **2019-06**, mBio, DOI: 10.1128/mBio.02577-18, https://doi.org/10.1128/mbio.02577-18 (pqac-00000000, pqac-00000004) |
| **Cofactor requirement:** HglS is an **Fe(II)-dependent metalloenzyme** | EDTA treatment abolished activity; after apo-enzyme preparation, **only Fe(II)** reconstituted catalysis. Standard assay conditions reported included **5 mM 2OA**, **10 µM purified enzyme**, **50 mM HEPES**, **16 h at 30°C** for endpoint assays (pqac-00000000, pqac-00000005) | Metal-dependence assay; reconstitution biochemistry | Thompson et al., **2019-06**, mBio, DOI: 10.1128/mBio.02577-18, https://doi.org/10.1128/mbio.02577-18 (pqac-00000000, pqac-00000005) |
| **Kinetics with 2OA substrate:** HglS shows measurable Michaelis-Menten behavior on 2OA | **Km = 0.06 mM ± 0.03**, **Vmax = 0.33 mM/min ± 0.08**, **kcat = 330 min⁻¹** (as reported); kinetic plot shown in Fig. 3E and reaction scheme in Fig. 3F (pqac-00000000, pqac-00000008) | Enzyme kinetics | Thompson et al., **2019-06**, mBio, DOI: 10.1128/mBio.02577-18, https://doi.org/10.1128/mbio.02577-18 (pqac-00000000, pqac-00000008) |
| **Physiological role:** HglS is required for lysine catabolism feeding into central metabolism | A **ΔPP_5260** mutant **cannot grow on either lysine isomer**; RB-TnSeq identified PP_5260 as important in lysine utilization, placing the enzyme in the 2OA catabolic segment of the pathway (pqac-00000000, pqac-00000004, pqac-00000006) | Genetics; fitness profiling; growth phenotype | Thompson et al., **2019-06**, mBio, DOI: 10.1128/mBio.02577-18, https://doi.org/10.1128/mbio.02577-18 (pqac-00000000, pqac-00000004, pqac-00000006) |
| **Mechanistic description:** the chemistry is an unusual decarboxylative/hydroxylative transformation of 2OA to D-2HG | Authors describe the transformation as an unusual route of **decarboxylation** with **hydroxylation-like** chemistry; later structural/mechanistic evidence indicates **O2 consumption in 1:1 stoichiometry with substrate** and incorporation of oxygen from O2 into product (pqac-00000002, pqac-00000003) | Biochemical interpretation; O2-consumption/isotope evidence | Thompson dissertation/associated mechanistic work, **2019**, excerpted evidence with structural/biochemical data (pqac-00000003); Thompson et al., **2019-06**, mBio, https://doi.org/10.1128/mbio.02577-18 (pqac-00000002) |


*Table: This table compiles the experimentally supported biochemical claims for *P. putida* KT2440 HglS/PP_5260, including reaction, stereochemistry, Fe(II) dependence, kinetics, and assay conditions. It is useful for linking UniProt annotation of Q88CC1 to the primary enzymology and physiological evidence in the literature.*