Component

Retinol dehydrogenase 12 / RDH12

Photoreceptor inner-segment retinal reductase.

2 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. Mouse rod imaging identified RDH12-dependent reduction of retinaldehyde entering inner segments from the outer segment or extracellular medium.

    Retinol dehydrogenase 12 / RDH12 → Photoreceptor retinaldehyde reduction source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    Knockout rod imaging and exogenous retinal challenge
    limitations
    The inferred protection of organelles is not itself a clinical outcome.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Mus musculus
    plain_language
    RDH12 helps clear retinal that reaches the cell interior.
    primary_references
    [chen-2012] Reduction of all-trans-retinal in vertebrate rod photoreceptors requires the combined action of RDH8 and RDH12 (2012). https://pubmed.ncbi.nlm.nih.gov/22621924/ DOI: 10.1074/jbc.M112.354514
    tissue_or_cell_type
    Rod inner segment

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 767–776

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Knockout rod imaging and exogenous retinal challenge · source_derived_draft · unverified_draft

    ### a-vision-rdh12-reduction Mouse rod imaging identified RDH12-dependent reduction of retinaldehyde entering inner segments from the outer segment or extracellular medium. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: RDH12 helps clear retinal that reaches the cell interior. organism: Mus musculus tissue_or_cell_type: Rod inner segment experimental_model: Knockout rod imaging and exogenous retinal challenge limitations: The inferred protection of organelles is not itself a clinical outcome. [chen-2012] Reduction of all-trans-retinal in vertebrate rod photoreceptors requires the combined action of RDH8 and RDH12 (2012). https://pubmed.ncbi.nlm.nih.gov/22621924/ DOI: 10.1074/jbc.M112.354514
    Complete structured claim and evidence

What acts on it

  1. Purified human RDH12 used NADPH for retinal reduction and had much lower apparent cofactor Km for NADP(H) than NAD(H).

    NADPH → Retinol dehydrogenase 12 / RDH12 source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    Purified-enzyme cofactor/substrate kinetics
    limitations
    Biochemical cofactor preference does not demonstrate a dietary niacin-deficiency visual phenotype.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Homo sapiens protein
    plain_language
    The reductase uses NADPH reducing power to convert retinal into retinol.
    primary_references
    [belyaeva-2005] Biochemical properties of purified human retinol dehydrogenase 12 (RDH12): catalytic efficiency toward retinoids and C9 aldehydes and effects of cellular retinol-binding protein type I (CRBPI) and cellular retinaldehyde-binding protein (CRALBP) on the oxidation and reduction of retinoids (2005). https://pubmed.ncbi.nlm.nih.gov/15865448/ DOI: 10.1021/bi050226k
    tissue_or_cell_type
    Recombinant enzyme preparation

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 778–787

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified-enzyme cofactor/substrate kinetics · source_derived_draft · unverified_draft

    ### a-vision-rdh12-nadph Purified human RDH12 used NADPH for retinal reduction and had much lower apparent cofactor Km for NADP(H) than NAD(H). Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: The reductase uses NADPH reducing power to convert retinal into retinol. organism: Homo sapiens protein tissue_or_cell_type: Recombinant enzyme preparation experimental_model: Purified-enzyme cofactor/substrate kinetics limitations: Biochemical cofactor preference does not demonstrate a dietary niacin-deficiency visual phenotype. [belyaeva-2005] Biochemical properties of purified human retinol dehydrogenase 12 (RDH12): catalytic efficiency toward retinoids and C9 aldehydes and effects of cellular retinol-binding protein type I (CRBPI) and cellular retinaldehyde-binding protein (CRALBP) on the oxidation and reduction of retinoids (2005). https://pubmed.ncbi.nlm.nih.gov/15865448/ DOI: 10.1021/bi050226k
    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