Component

4-Hydroxy-all-trans-retinoic acid

Hydroxylated all-trans-retinoic-acid metabolite; C4 stereochemistry unspecified in these pooled assays.

3 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What acts on it

  1. Recombinant human CYP26A1 hydroxylated all-trans-retinoic acid to 4-hydroxy-retinoic acid.

    Cytochrome P450 26A1 / CYP26A1 → 4-Hydroxy-all-trans-retinoic acid source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    NADPH and heme-containing P450 machinery support retinoid oxidation; nutritional deficiency was not tested.
    evidence_location
    Abstract
    experimental_model
    Human CYP26A1/CYP26B1 expressed in insect cells; purified/reconstituted metabolism and tissue assays.
    exposure
    All-trans-retinoic-acid concentration series with P450 reductase and NADPH.
    limitations
    Assay kinetics are not whole-body clearance; hydroxylated products are not assumed biologically inert.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Homo sapiens recombinant protein in insect cells
    outcome
    Recombinant human CYP26A1 hydroxylated all-trans-retinoic acid to 4-hydroxy-retinoic acid.
    plain_language
    This P450 begins oxidative removal of the signaling retinoid.
    primary_references
    [va-topletz-2012] Comparison of the function and expression of CYP26A1 and CYP26B1, the two retinoic acid hydroxylases (2012). https://pubmed.ncbi.nlm.nih.gov/22020119/ DOI: 10.1016/j.bcp.2011.10.007
    tissue_or_cell_type
    Reconstituted enzyme/microsomes

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 601–614

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human CYP26A1/CYP26B1 expressed in insect cells; purified/reconstituted metabolism and tissue assays. · source_derived_draft · unverified_draft

    ### va-cyp26a1-primary-hydroxylation Recombinant human CYP26A1 hydroxylated all-trans-retinoic acid to 4-hydroxy-retinoic acid. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: This P450 begins oxidative removal of the signaling retinoid. organism: Homo sapiens recombinant protein in insect cells tissue_or_cell_type: Reconstituted enzyme/microsomes experimental_model: Human CYP26A1/CYP26B1 expressed in insect cells; purified/reconstituted metabolism and tissue assays. limitations: Assay kinetics are not whole-body clearance; hydroxylated products are not assumed biologically inert. exposure: All-trans-retinoic-acid concentration series with P450 reductase and NADPH. outcome: Recombinant human CYP26A1 hydroxylated all-trans-retinoic acid to 4-hydroxy-retinoic acid. evidence_location: Abstract cross_nutrient: NADPH and heme-containing P450 machinery support retinoid oxidation; nutritional deficiency was not tested. [va-topletz-2012] Comparison of the function and expression of CYP26A1 and CYP26B1, the two retinoic acid hydroxylases (2012). https://pubmed.ncbi.nlm.nih.gov/22020119/ DOI: 10.1016/j.bcp.2011.10.007
    Complete structured claim and evidence

  2. Recombinant human CYP26B1 formed 4-hydroxy-retinoic acid from all-trans-retinoic acid.

    Cytochrome P450 26B1 / CYP26B1 → 4-Hydroxy-all-trans-retinoic acid source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Abstract
    experimental_model
    Human CYP26A1/CYP26B1 expressed in insect cells; purified/reconstituted metabolism and tissue assays.
    exposure
    Substrate series with NADPH and P450 reductase.
    limitations
    Lower in vitro turnover than CYP26A1 does not mean lower importance in every tissue.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Homo sapiens recombinant protein in insect cells
    outcome
    Recombinant human CYP26B1 formed 4-hydroxy-retinoic acid from all-trans-retinoic acid.
    plain_language
    A second independent P450 enzyme also removes the signaling precursor.
    primary_references
    [va-topletz-2012] Comparison of the function and expression of CYP26A1 and CYP26B1, the two retinoic acid hydroxylases (2012). https://pubmed.ncbi.nlm.nih.gov/22020119/ DOI: 10.1016/j.bcp.2011.10.007
    tissue_or_cell_type
    Reconstituted enzyme/microsomes

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 616–628

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human CYP26A1/CYP26B1 expressed in insect cells; purified/reconstituted metabolism and tissue assays. · source_derived_draft · unverified_draft

    ### va-cyp26b1-primary-hydroxylation Recombinant human CYP26B1 formed 4-hydroxy-retinoic acid from all-trans-retinoic acid. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: A second independent P450 enzyme also removes the signaling precursor. organism: Homo sapiens recombinant protein in insect cells tissue_or_cell_type: Reconstituted enzyme/microsomes experimental_model: Human CYP26A1/CYP26B1 expressed in insect cells; purified/reconstituted metabolism and tissue assays. limitations: Lower in vitro turnover than CYP26A1 does not mean lower importance in every tissue. exposure: Substrate series with NADPH and P450 reductase. outcome: Recombinant human CYP26B1 formed 4-hydroxy-retinoic acid from all-trans-retinoic acid. evidence_location: Abstract [va-topletz-2012] Comparison of the function and expression of CYP26A1 and CYP26B1, the two retinoic acid hydroxylases (2012). https://pubmed.ncbi.nlm.nih.gov/22020119/ DOI: 10.1016/j.bcp.2011.10.007
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. CYP26A1 further metabolized 4-hydroxy-all-trans-retinoic acid.

    Cytochrome P450 26A1 / CYP26A1 → Oxidative clearance of retinoic-acid metabolites source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Abstract
    experimental_model
    Human CYP26A1/CYP26B1 expressed in insect cells; purified/reconstituted metabolism and tissue assays.
    exposure
    Incubation with 4-hydroxy-all-trans-retinoic acid.
    limitations
    This assay does not assign every downstream metabolite a structure or biological inactivity.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Homo sapiens recombinant protein
    outcome
    CYP26A1 further metabolized 4-hydroxy-all-trans-retinoic acid.
    plain_language
    Oxidation continues beyond the first hydroxylated product.
    primary_references
    [va-topletz-2012] Comparison of the function and expression of CYP26A1 and CYP26B1, the two retinoic acid hydroxylases (2012). https://pubmed.ncbi.nlm.nih.gov/22020119/ DOI: 10.1016/j.bcp.2011.10.007
    tissue_or_cell_type
    Reconstituted enzyme

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 630–642

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human CYP26A1/CYP26B1 expressed in insect cells; purified/reconstituted metabolism and tissue assays. · source_derived_draft · unverified_draft

    ### va-cyp26a1-secondary-metabolism CYP26A1 further metabolized 4-hydroxy-all-trans-retinoic acid. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Oxidation continues beyond the first hydroxylated product. organism: Homo sapiens recombinant protein tissue_or_cell_type: Reconstituted enzyme experimental_model: Human CYP26A1/CYP26B1 expressed in insect cells; purified/reconstituted metabolism and tissue assays. limitations: This assay does not assign every downstream metabolite a structure or biological inactivity. exposure: Incubation with 4-hydroxy-all-trans-retinoic acid. outcome: CYP26A1 further metabolized 4-hydroxy-all-trans-retinoic acid. evidence_location: Abstract [va-topletz-2012] Comparison of the function and expression of CYP26A1 and CYP26B1, the two retinoic acid hydroxylases (2012). https://pubmed.ncbi.nlm.nih.gov/22020119/ DOI: 10.1016/j.bcp.2011.10.007
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

    Evidence, AI assistance and curation standards