Component

RPE65 retinoid isomerohydrolase

Iron-dependent retinyl ester isomerohydrolase.

5 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 it acts on

  1. Overexpressed human RPE65 supported conversion of lutein into meso-zeaxanthin in cultured cells.

    RPE65 retinoid isomerohydrolase → meso-Zeaxanthin / (3R,3-prime-S)-zeaxanthin source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/lutein-research/28874556.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "240bde60bb175fdfd5f556b9f2f7aab97f5d5b03e9640160418c34c74194d8c9", "start_char": 0, "end_char": 1679, "text_sha256": "240bde60bb175fdfd5f556b9f2f7aab97f5d5b03e9640160418c34c74194d8c9"}
    experimental_model
    Overexpression, developmental expression and pharmacological inhibition
    exposure
    RPE65 expression with lutein; inhibitor experiments in developing chicken eye
    limitations
    Cell and animal evidence; docking near iron is not a human iron-supplementation experiment.
    nutrient_topic
    Lutein research collection; topical membership is not evidence of a direct dietary effect. · Lutein
    organism
    Human/chicken proteins in cells and chicken embryos
    plain_language
    The visual-cycle enzyme can also rearrange lutein.
    primary_references
    [lutein-p28874556] RPE65 has an additional function as the lutein to meso-zeaxanthin isomerase in the vertebrate eye. (2017). https://pubmed.ncbi.nlm.nih.gov/28874556/ DOI: 10.1073/pnas.1706332114
    tissue_or_cell_type
    Cultured cells and embryonic RPE/choroid

    Lutein: metabolism, signaling and nutrient connections (2026-09-17) · lines 151–162

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Overexpression, developmental expression and pharmacological inhibition · source_derived_draft · unverified_draft

    ### lutein-human-rpe65-isomerase Overexpressed human RPE65 supported conversion of lutein into meso-zeaxanthin in cultured cells. Condition category: normal nutrient_topic: Lutein research collection; topical membership is not evidence of a direct dietary effect. plain_language: The visual-cycle enzyme can also rearrange lutein. organism: Human/chicken proteins in cells and chicken embryos tissue_or_cell_type: Cultured cells and embryonic RPE/choroid experimental_model: Overexpression, developmental expression and pharmacological inhibition limitations: Cell and animal evidence; docking near iron is not a human iron-supplementation experiment. exposure: RPE65 expression with lutein; inhibitor experiments in developing chicken eye evidence_span: {"source_cache": "artifacts/lutein-research/28874556.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "240bde60bb175fdfd5f556b9f2f7aab97f5d5b03e9640160418c34c74194d8c9", "start_char": 0, "end_char": 1679, "text_sha256": "240bde60bb175fdfd5f556b9f2f7aab97f5d5b03e9640160418c34c74194d8c9"} [lutein-p28874556] RPE65 has an additional function as the lutein to meso-zeaxanthin isomerase in the vertebrate eye. (2017). https://pubmed.ncbi.nlm.nih.gov/28874556/ DOI: 10.1073/pnas.1706332114
    Complete structured claim and evidence

  2. Recombinant RPE65 catalyzed conversion of all-trans-retinyl esters to 11-cis-retinol in visual-cycle reconstitution.

    RPE65 retinoid isomerohydrolase → 11-cis-retinol source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    Recombinant enzyme reconstitution
    limitations
    Production of the aldehyde requires a subsequent oxidation step.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    QBI-293A human cells and COS-1 monkey cells
    plain_language
    RPE65 converts the ester pool into the cis alcohol needed for chromophore renewal.
    primary_references
    [moiseyev-2005] RPE65 is the isomerohydrolase in the retinoid visual cycle (2005). https://pubmed.ncbi.nlm.nih.gov/16116091/ DOI: 10.1073/pnas.0503460102
    tissue_or_cell_type
    RPE visual-cycle biochemical model

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 666–675

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant enzyme reconstitution · source_derived_draft · unverified_draft

    ### a-vision-rpe65-isomerization Recombinant RPE65 catalyzed conversion of all-trans-retinyl esters to 11-cis-retinol in visual-cycle reconstitution. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: RPE65 converts the ester pool into the cis alcohol needed for chromophore renewal. organism: QBI-293A human cells and COS-1 monkey cells tissue_or_cell_type: RPE visual-cycle biochemical model experimental_model: Recombinant enzyme reconstitution limitations: Production of the aldehyde requires a subsequent oxidation step. [moiseyev-2005] RPE65 is the isomerohydrolase in the retinoid visual cycle (2005). https://pubmed.ncbi.nlm.nih.gov/16116091/ DOI: 10.1073/pnas.0503460102
    Complete structured claim and evidence

What acts on it

  1. FeSO4 restored chelator-inhibited RPE65 isomerohydrolase activity in bovine microsomes and recombinant assays; ferric salts did not.

    Ferrous iron → RPE65 retinoid isomerohydrolase source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Iron availability at RPE65 enables formation of the cis-retinoid visual-cycle intermediate.
    experimental_model
    Chelation and metal rescue
    limitations
    This is enzyme-cofactor evidence, not a human iron-deficiency threshold.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Bos taurus; recombinant RPE65 in human 293A cells
    plain_language
    Ferrous iron is required for this vitamin A recycling enzyme.
    primary_references
    [moiseyev-2006] RPE65 is an iron(II)-dependent isomerohydrolase in the retinoid visual cycle (2006). https://pubmed.ncbi.nlm.nih.gov/16319067/ DOI: 10.1074/jbc.M508903200
    tissue_or_cell_type
    RPE microsomes and cultured-cell preparations

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 677–687

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Chelation and metal rescue · source_derived_draft · unverified_draft

    ### a-vision-rpe65-iron FeSO4 restored chelator-inhibited RPE65 isomerohydrolase activity in bovine microsomes and recombinant assays; ferric salts did not. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Ferrous iron is required for this vitamin A recycling enzyme. organism: Bos taurus; recombinant RPE65 in human 293A cells tissue_or_cell_type: RPE microsomes and cultured-cell preparations experimental_model: Chelation and metal rescue limitations: This is enzyme-cofactor evidence, not a human iron-deficiency threshold. cross_nutrient: Iron availability at RPE65 enables formation of the cis-retinoid visual-cycle intermediate. [moiseyev-2006] RPE65 is an iron(II)-dependent isomerohydrolase in the retinoid visual cycle (2006). https://pubmed.ncbi.nlm.nih.gov/16319067/ DOI: 10.1074/jbc.M508903200
    Complete structured claim and evidence

  2. ZnCl2 did not restore isomerohydrolase activity after metal chelation in the bovine RPE assay, whereas FeSO4 did.

    Zinc(II) ion → RPE65 retinoid isomerohydrolase source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Iron and zinc are not interchangeable RPE65 cofactors in the tested preparation.
    experimental_model
    Metal-rescue comparison
    limitations
    Does not test systemic zinc status or other zinc-dependent visual functions.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Bos taurus
    plain_language
    Zinc could not replace iron in this enzyme assay.
    primary_references
    [moiseyev-2006] RPE65 is an iron(II)-dependent isomerohydrolase in the retinoid visual cycle (2006). https://pubmed.ncbi.nlm.nih.gov/16319067/ DOI: 10.1074/jbc.M508903200
    tissue_or_cell_type
    RPE microsomes

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 689–699

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Metal-rescue comparison · source_derived_draft · unverified_draft

    ### a-vision-rpe65-zinc-not-substitute ZnCl2 did not restore isomerohydrolase activity after metal chelation in the bovine RPE assay, whereas FeSO4 did. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Zinc could not replace iron in this enzyme assay. organism: Bos taurus tissue_or_cell_type: RPE microsomes experimental_model: Metal-rescue comparison limitations: Does not test systemic zinc status or other zinc-dependent visual functions. cross_nutrient: Iron and zinc are not interchangeable RPE65 cofactors in the tested preparation. [moiseyev-2006] RPE65 is an iron(II)-dependent isomerohydrolase in the retinoid visual cycle (2006). https://pubmed.ncbi.nlm.nih.gov/16319067/ DOI: 10.1074/jbc.M508903200
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Intravitreal adenovirus expressing human DES1 increased retinal 9-cis-retinal in Rpe65-null mice relative to the RFP control virus.

    Adenoviral DES1 expression → 9-cis-retinal source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    cross_nutrient
    false
    evidence_location
    Figure 4a; Results: Gene therapy of rpe65-null mice
    experimental_model
    Adenoviral human DES1 versus RFP in Rpe65-null mice
    exposure
    Retinoids measured one day after injection; Figure 4a without added intravitreal retinol.
    limitations
    11-cis-retinoids remained undetectable in this comparison; viral cell targeting was not exclusive.
    nutrient
    Vitamin A · Vitamin A
    nutrient_topic
    Vitamin A expansion research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Homo sapiens transgene in Mus musculus
    plain_language
    Extra DES1 increased an alternative cis-retinal isomer in the mutant eyes.
    primary_references
    [vav-kaylor2013] Identification of DES1 as a vitamin A isomerase in Müller glial cells of the retina. (2013). https://pubmed.ncbi.nlm.nih.gov/23143414/ DOI: 10.1038/nchembio.1114
    tissue_or_cell_type
    retina
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Vitamin A expansion: reproduction, light-driven vision and shared mechanisms (2026-09-17) · lines 603–616

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Adenoviral human DES1 versus RFP in Rpe65-null mice · source_derived_draft · unverified_draft

    ### vae-des1-gene-transfer-9cis Intravitreal adenovirus expressing human DES1 increased retinal 9-cis-retinal in Rpe65-null mice relative to the RFP control virus. Condition category: machinery_impairment nutrient_topic: Vitamin A expansion research collection; topical membership is not evidence of a direct dietary effect. plain_language: Extra DES1 increased an alternative cis-retinal isomer in the mutant eyes. organism: Homo sapiens transgene in Mus musculus tissue_or_cell_type: retina experimental_model: Adenoviral human DES1 versus RFP in Rpe65-null mice limitations: 11-cis-retinoids remained undetectable in this comparison; viral cell targeting was not exclusive. exposure: Retinoids measured one day after injection; Figure 4a without added intravitreal retinol. cross_nutrient: false evidence_location: Figure 4a; Results: Gene therapy of rpe65-null mice nutrient: Vitamin A [vav-kaylor2013] Identification of DES1 as a vitamin A isomerase in Müller glial cells of the retina. (2013). https://pubmed.ncbi.nlm.nih.gov/23143414/ DOI: 10.1038/nchembio.1114
    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.

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