CYP4V2 is an ER-associated, heme-containing fatty-acid hydroxylase. Reconstituted human enzyme directly makes terminal hydroxy products from laurate, myristate and palmitate. The inspected kinetic Results favor myristate, while the C8 assay was negative. The paper’s use of “medium-chain” includes C14, whereas current GO places C14 in its C13–C22 long-chain class; the separate C6–C12 term captures the positive laurate reaction. PMID:19661213(https://pubmed.ncbi.nlm.nih.gov/19661213/)
Purified human CYP4V2 also forms 20-hydroxy-EPA and 22-hydroxy-DHA. Actual Figure 5 separates biosynthetic standards, minus-NADPH controls and CYP4V2 turnover. Smaller 19-hydroxy-EPA and 21-hydroxy-DHA products establish a secondary penultimate-carbon outcome; they were not separately quantified. Terminal-product quantitation used saturated same-chain standards, and substrate solubility/inhibition prevented exhaustive kinetics. These data support three complementary catalytic activities without asserting equal physiological importance. PMID:22772592(https://pubmed.ncbi.nlm.nih.gov/22772592/)
The same study reports endogenous ARPE-19 CYP4V2 colocalization with calreticulin and ocular epithelial staining. The original main Methods/Results were read, but the supplemental localization figure was not recovered: a URL ending in PDF returned download/challenge HTML. The predicted N-terminal membrane anchor is distinct from experimentally resolved orientation. H331P-transduced HepG2 cells had reduced protein and altered PUFA pools; this does not establish the entire retinal disease mechanism or directly compare turnover per equal amount of variant enzyme. The initial disease-discovery abstract establishes autosomal-recessive Bietti crystalline dystrophy, while its suggested fatty-acid/steroid functions were hypotheses later refined by direct chemistry. PMID:15042513(https://pubmed.ncbi.nlm.nih.gov/15042513/)
Actual Reactome catalyst/entity/reference paths identify the full 525-residue CYP4V2 protein converting DHA to 22-hydroxy-DHA in ER membrane. Both the retinoid-cycle and endogenous-sterol parent pathways contain this child. The substrates are neither retinoids nor sterols under the checked GO definitions, so those two process mappings overstate the specific reaction. This is not a claim that every possible retinoid/sterol substrate has been experimentally excluded. The net reaction’s NADPH consumption also does not make NADPH the direct donor: the P450 receives electrons via reductase. Reactome reaction
Two exact IntAct records link tagged CYP4V2 bait to GATC prey in HEK293T anti-tag co-IP experiments. GATC is the mitochondrial amidotransferase structural subunit, not an established electron-transfer partner for CYP4V2. The associations remain contextual evidence without a binary-interface, native retinal complex or mitochondrial translation claim. The 2017 clone/AP-MS Methods were read. The 2021 cache contains introduction/discussion but lacks Methods despite its full-text flag; its precise assay metadata are attributed to IntAct. PMID:28514442(https://pubmed.ncbi.nlm.nih.gov/28514442/) PMID:33961781(https://pubmed.ncbi.nlm.nih.gov/33961781/)
The official displayed product has 525 residues. VSP_014918 deletes residues 42–63 to produce the 503-residue splice form. Tagged full-coding experimental constructs do not establish equivalent activity or localization of that shorter form. Cofactor-binding residue assignments are homology inferences, while purified target mass and reduced-CO spectroscopy provide direct heme-protein evidence. Disease necessity, retinal expression and interaction screens were not converted into speculative NEW process annotations.
All 17 genuine seeded source objects remain intact. Source-specific refinements distinguish medium-chain omega, long-chain omega and long-chain omega-1 chemistry; no new annotation is added. The public source guide records primary and official database locators, chemical paths and access limits. The 2009 fetched main text lacks actual Table 1 values/captions; original HTML returned a challenge and the publisher PDF returned 403. No exact table or figure-pixel read is claimed for that paper. The 2012 original Figure 5 was personally inspected. Background sequence/phosphoproteome references were read at cached abstract scope and do not establish additional CYP4V2 functions.
Normal isolated fetches supplied the source files. Default Falcon failed with authentication HTTP 403 and configured perplexity-lite failed with quota HTTP 401; no provider research report was fabricated. Main source/context files and the separate pending PTHR24291 variant were preserved. No full family-tree analysis is asserted: this seed contains no IBA rows. The key biological questions remain the disease-relevant endogenous substrate pool, the role of minor omega-1 products, and the function of the shorter splice product.
The two supported CYP4V2–GATC associations remain contextual. The ClinGen project curation instructions explicitly record the user's direction to retain supported generic binding as KEEP_AS_NON_CORE when no more informative molecular function is established. They also explicitly identify this as a task-specific departure from the repository-wide informational-exclusion recommendation. The repository validator implements that broader recommendation and is current; its warning is expected for this project exception. The earlier history's word “legacy” referred imprecisely to the advisory's applicability, not its commit date. That immutable record is preserved, and this clarification supersedes that wording. Neither reported association supplies evidence for a specific catalytic partnership or a retinal protein complex.
The retinoid and sterol decisions intentionally flag excessive process specificity propagated from real Reactome pathway membership. The actual target event remains DHA hydroxylation. Its performed chemistry and ocular/lipid context are supported, while a performed retinoid/sterol step or structural/cofactor contribution to one is unestablished in the inspected path. MARK_AS_OVER_ANNOTATED records this conservative source-scope judgment; it does not claim a comprehensive negative substrate screen. The two MISCITED assessments concern support for those precise GO-process assertions, while preserving the genuine pathway/event topology.
Seven short, exact excerpts now anchor both fatty-acid omega-oxidation IDA reviews, both primary-reference findings and all three catalytic cores. The excerpts are checked against unchanged cached publications. Aggregate quotations are kept within 25 words for each source, including repeated product names. The original full-text, Figure 5 and source-access scopes remain as documented above; no new retrieval or figure inspection is claimed. The missing original Table 1 cells remain missing. The secondary omega-1 activity is supported by identified enzyme products and remains explicitly unquantified; the source-level MODIFY refinement is retained without creating a NEW row.
Both official products and their identity/reconstruction fields remain unchanged. Distinct functional classes for the shorter splice product are still unestablished. Status continues to be derived by the normal tool; it is not forced to COMPLETE to suppress the expected project-policy warnings. All 17 imported source objects, 19 reference identities, prior notes and history are preserved.