All 75 original annotation rows and source references were reviewed, including all duplicate experimental steroid reactions and Reactome catalytic/localization contexts. Exact source fields are preserved. No NEW row is added.
PMID:21851338 full accepted manuscript, HAL PDF: Methods, Results, Figure 1 and Table 1 were read. Purified AKR1C4 reduced all-trans- and 9-cis-retinaldehyde to retinol with NADPH; HPLC standards distinguished retinal and retinol. Exact excerpt: “AKR1C3 and AKR1C4 exhibited low Km and kcat values”. The oxidative retinol assays used NADP+, and all-trans-retinol oxidation was not detected. GO:0001758 instead specifies retinal oxidation to retinoate with NAD+, not the reverse of this reductase reaction. GO:0052650 captures the demonstrated reversible reaction chemistry without claiming efficient retinol oxidation in the tested conditions. HeLa reporter experiments link expressed AKR1C4 to reduced retinoic-acid receptor activation but do not demonstrate retinal-to-retinoate catalysis.
PMID:19487289 full author-hosted Cancer Research PDF: recombinant enzyme methods, Figure 2 inhibition, cell-based Results/Figures 3–5 and Discussion were checked. All four recombinant AKR1Cs were assayed with phenanthrenequinone. AKR1C4 inhibition by jasmonic acid was measurable (Ki 18 ± 3 micromolar); methyl-jasmonate inhibition was undetermined at the tested concentrations. The downstream cellular PGD2/leukemia experiments focused on AKR1C3. Purified C4 inhibition establishes a biochemical interaction, but a C4-specific cellular response assignment needs separate support. Human response to a xenobiotic does not require an endogenous plant jasmonate signaling pathway.
PMID:20003443 full PMC article read including Methods, Results, Table 1, Figure 4 and Discussion. Exact excerpt: “All purified proteins were able to reduce the pan-substrate 9, 10-phenanthrenequinone”. This supports C4 quinone-reductase capacity independently of interpreting the anthracycline reaction in PMID:20837989. The radiochemical assays compared PGD2/PGE2/PGH2 at 150 micromolar NADPH; results distinguish PGD2 activity of C3 and PGE2 activity absent in the tested human isoforms. They do not provide a comprehensive negative C4 result for every prostaglandin transformation. The authors explicitly discuss assay sensitivity and failures to detect low steroid activities. Crucially, the published correction, DOI:10.1186/1476-4598-9-21 states: “The experiments in this study used androstanedione as a test substrate.” The original paper's androstenedione labels must not be used as proof of that different substrate reaction. The correction was verified from its primary full text and university publication record; the repository PMID fetch for 20109200 failed and no identifier remapping is inferred.
PMID:21802064 full PMC article shows AKR1C4 expression in fetal testis and adrenal and direct DHP-to-allopregnanolone assays, despite very low adult-testis expression. Adult liver predominance is not absolute tissue restriction. PMID:19218247 full PMC enzymology demonstrates C4 reduction of unconjugated and conjugated DHT substrates. Original steroid enzymology abstracts PMID:10998348, 14672942, 7650035, 10634139, 11158055, 2187532 and 2427522 support the retained catalytic rows. The apparent full-text cache for 10998348 contains an abstract/PDF link only; this was not mistaken for a full-paper read.
PMID:23533145 full urinary-exosome proteomics paper: Methods and Results support a curated proteomic compartment observation, not a new extracellular catalytic role. Cytosolic localization does not exclude vesicle-associated detection.
AKR1C4-paint-lineage.json records actual P17516 leaf PTN002482510 ancestry in PTHR11732. Root PTN000198921 carries aldose reduction/cytosol; PTN000199026 carries steroid dehydrogenase and ketosteroid monooxygenase; PTN000199031 carries androsterone, bile-acid binding, prostaglandin/progesterone and anthracycline processes. No matching target-path loss was recovered. GO:0004032 describes aldose/alditol chemistry, not a generic name for every AKR. GO:0047086 requires O2/NADPH-dependent progesterone-to-testosterone-acetate monooxygenation, not ketone reduction.
Live QuickGO traces monooxygenase evidence for human AKR1C1/C2/C3 to IDA PMID:21232532, an endometriosis study whose accessible abstract measures expression. The full relevant source was not obtained; neither wrong-gene attribution nor chemical impossibility is asserted from that abstract. Prostaglandin IBD grounding includes AKR1C2 as well as C3 (PMID:8573067 and 9792917), so the old C3-only explanation is inaccurate. PMID:8573067 revises the old DD1/DD2 nomenclature, and PMID:8172617 distinguishes the C9 bile-acid-binder clone from C11/DD4. The latter full scanned paper remains inaccessible. These observations do not by themselves exclude free bile-acid binding, carrier behavior, or a transport process by C4. Binding is retained as inherited non-core capacity; exact transmembrane transport and broader transport remain unresolved independently.
No prior target OpenScientist report was found in the folder/global cache. The focused aldose-prostaglandin-monooxygenase-and-bile-transport-scope request is gated under launcher 45234; it is not yet claimed remotely submitted. PMID:20003443, its correction and the nomenclature clarification in 8573067 are post-launch evidence leads for critical assessment of that report.