Component

Human beta-carotene oxygenase 2 / BCO2

Human beta-carotene oxygenase 2 / BCO2. Species, exposure and limitations are retained in each linked claim.

6 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. Human BCO2 binding to tested macular carotenoids was 10–40-fold weaker than mouse BCO2 in the 2014 comparison.

    Human beta-carotene oxygenase 2 / BCO2 → Lutein source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/lutein-research/24982131.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "975bef59c81c57ad6e18b45581b23174165732965e8d7e017275fe98ca3ab4a0", "start_char": 0, "end_char": 1743, "text_sha256": "975bef59c81c57ad6e18b45581b23174165732965e8d7e017275fe98ca3ab4a0"}
    experimental_model
    Recombinant enzyme expression and comparative binding
    exposure
    Zeaxanthin-producing bacteria; surface plasmon resonance
    limitations
    Historical assay result; later work demonstrates human catalytic competence with altered protein processing and expression conditions.
    nutrient_topic
    Lutein research collection; topical membership is not evidence of a direct dietary effect. · Lutein
    organism
    Human and mouse proteins; bacterial expression
    plain_language
    The early protein preparations differed in pigment binding.
    primary_references
    [lutein-p24982131] Inactivity of human β,β-carotene-9',10'-dioxygenase (BCO2) underlies retinal accumulation of the human macular carotenoid pigment. (2014). https://pubmed.ncbi.nlm.nih.gov/24982131/ DOI: 10.1073/pnas.1402526111
    tissue_or_cell_type
    Recombinant BCO2 and retina

    Lutein: metabolism, signaling and nutrient connections (2026-09-17) · lines 268–279

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

    ### lutein-bco2-2014-binding Human BCO2 binding to tested macular carotenoids was 10–40-fold weaker than mouse BCO2 in the 2014 comparison. Condition category: normal nutrient_topic: Lutein research collection; topical membership is not evidence of a direct dietary effect. plain_language: The early protein preparations differed in pigment binding. organism: Human and mouse proteins; bacterial expression tissue_or_cell_type: Recombinant BCO2 and retina experimental_model: Recombinant enzyme expression and comparative binding limitations: Historical assay result; later work demonstrates human catalytic competence with altered protein processing and expression conditions. exposure: Zeaxanthin-producing bacteria; surface plasmon resonance evidence_span: {"source_cache": "artifacts/lutein-research/24982131.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "975bef59c81c57ad6e18b45581b23174165732965e8d7e017275fe98ca3ab4a0", "start_char": 0, "end_char": 1743, "text_sha256": "975bef59c81c57ad6e18b45581b23174165732965e8d7e017275fe98ca3ab4a0"} [lutein-p24982131] Inactivity of human β,β-carotene-9',10'-dioxygenase (BCO2) underlies retinal accumulation of the human macular carotenoid pigment. (2014). https://pubmed.ncbi.nlm.nih.gov/24982131/ DOI: 10.1073/pnas.1402526111
    Complete structured claim and evidence

  2. The 2014 expression assay detected zeaxanthin cleavage by mouse BCO2 but not human BCO2.

    Human beta-carotene oxygenase 2 / BCO2 → Human BCO2 carotenoid cleavage activity source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/lutein-research/24982131.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "975bef59c81c57ad6e18b45581b23174165732965e8d7e017275fe98ca3ab4a0", "start_char": 0, "end_char": 1743, "text_sha256": "975bef59c81c57ad6e18b45581b23174165732965e8d7e017275fe98ca3ab4a0"}
    experimental_model
    Recombinant enzyme expression and comparative binding
    exposure
    Zeaxanthin-producing bacteria; surface plasmon resonance
    limitations
    Historical assay result; later work demonstrates human catalytic competence with altered protein processing and expression conditions.
    nutrient_topic
    Lutein research collection; topical membership is not evidence of a direct dietary effect. · Lutein
    organism
    Human and mouse proteins; bacterial expression
    plain_language
    One early assay found no detectable human enzyme activity.
    primary_references
    [lutein-p24982131] Inactivity of human β,β-carotene-9',10'-dioxygenase (BCO2) underlies retinal accumulation of the human macular carotenoid pigment. (2014). https://pubmed.ncbi.nlm.nih.gov/24982131/ DOI: 10.1073/pnas.1402526111
    tissue_or_cell_type
    Recombinant BCO2 and retina

    Lutein: metabolism, signaling and nutrient connections (2026-09-17) · lines 255–266

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

    ### lutein-bco2-2014-inactive The 2014 expression assay detected zeaxanthin cleavage by mouse BCO2 but not human BCO2. Condition category: normal nutrient_topic: Lutein research collection; topical membership is not evidence of a direct dietary effect. plain_language: One early assay found no detectable human enzyme activity. organism: Human and mouse proteins; bacterial expression tissue_or_cell_type: Recombinant BCO2 and retina experimental_model: Recombinant enzyme expression and comparative binding limitations: Historical assay result; later work demonstrates human catalytic competence with altered protein processing and expression conditions. exposure: Zeaxanthin-producing bacteria; surface plasmon resonance evidence_span: {"source_cache": "artifacts/lutein-research/24982131.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "975bef59c81c57ad6e18b45581b23174165732965e8d7e017275fe98ca3ab4a0", "start_char": 0, "end_char": 1743, "text_sha256": "975bef59c81c57ad6e18b45581b23174165732965e8d7e017275fe98ca3ab4a0"} [lutein-p24982131] Inactivity of human β,β-carotene-9',10'-dioxygenase (BCO2) underlies retinal accumulation of the human macular carotenoid pigment. (2014). https://pubmed.ncbi.nlm.nih.gov/24982131/ DOI: 10.1073/pnas.1402526111
    Complete structured claim and evidence

  3. Activity assays indicated interaction between BCO2 and intracellular carotenoid-transporting Aster proteins.

    Human beta-carotene oxygenase 2 / BCO2 → Aster intracellular carotenoid-transfer proteins; members unresolved in indexed abstract source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/lutein-research/39978586.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3546acef9586e54733ec1f03797741c67643606de59f80a7762815b32c3c03fe", "start_char": 0, "end_char": 1561, "text_sha256": "3546acef9586e54733ec1f03797741c67643606de59f80a7762815b32c3c03fe"}
    experimental_model
    Validated antibodies, localization, donor-retina analysis and activity assays
    exposure
    BCO2 precursor/processed protein comparison; Aster interactions
    limitations
    Protein expression and interaction evidence does not by itself quantify lutein cleavage in living human retina.
    nutrient_topic
    Lutein research collection; topical membership is not evidence of a direct dietary effect. · Lutein
    organism
    Human cells/donor retina and macaque retina
    plain_language
    Transport and breakdown machinery can work together in the assay.
    primary_references
    [lutein-p39978586] Unveiling BCO2 function in macular pigment metabolism: Mitochondrial processing and expression in the primate retina. (2025). https://pubmed.ncbi.nlm.nih.gov/39978586/ DOI: 10.1016/j.bbalip.2025.159600
    tissue_or_cell_type
    Retinal regions and mitochondria

    Lutein: metabolism, signaling and nutrient connections (2026-09-17) · lines 346–357

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Validated antibodies, localization, donor-retina analysis and activity assays · source_derived_draft · unverified_draft

    ### lutein-bco2-aster Activity assays indicated interaction between BCO2 and intracellular carotenoid-transporting Aster proteins. Condition category: normal nutrient_topic: Lutein research collection; topical membership is not evidence of a direct dietary effect. plain_language: Transport and breakdown machinery can work together in the assay. organism: Human cells/donor retina and macaque retina tissue_or_cell_type: Retinal regions and mitochondria experimental_model: Validated antibodies, localization, donor-retina analysis and activity assays limitations: Protein expression and interaction evidence does not by itself quantify lutein cleavage in living human retina. exposure: BCO2 precursor/processed protein comparison; Aster interactions evidence_span: {"source_cache": "artifacts/lutein-research/39978586.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3546acef9586e54733ec1f03797741c67643606de59f80a7762815b32c3c03fe", "start_char": 0, "end_char": 1561, "text_sha256": "3546acef9586e54733ec1f03797741c67643606de59f80a7762815b32c3c03fe"} [lutein-p39978586] Unveiling BCO2 function in macular pigment metabolism: Mitochondrial processing and expression in the primate retina. (2025). https://pubmed.ncbi.nlm.nih.gov/39978586/ DOI: 10.1016/j.bbalip.2025.159600
    Complete structured claim and evidence

  4. Human BCO2 associated with the inner mitochondrial membrane in cell-line experiments.

    Human beta-carotene oxygenase 2 / BCO2 → Inner mitochondrial membrane source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/lutein-research/25002123.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "13eecc413b623871f99140525333718bec180923ca6673fab15a9dee19a0551b", "start_char": 0, "end_char": 1308, "text_sha256": "13eecc413b623871f99140525333718bec180923ca6673fab15a9dee19a0551b"}
    experimental_model
    Subcellular localization and mitochondrial fractionation
    exposure
    Cleavable N-terminal leaders and compartment analyses
    limitations
    Human cell localization and mouse organelle fractionation are separate evidence components.
    nutrient_topic
    Lutein research collection; topical membership is not evidence of a direct dietary effect. · Lutein
    organism
    Human isoforms in cell lines and mouse liver
    plain_language
    Carotenoid breakdown is organized within a particular compartment.
    primary_references
    [lutein-p25002123] Evidence for compartmentalization of mammalian carotenoid metabolism. (2014). https://pubmed.ncbi.nlm.nih.gov/25002123/ DOI: 10.1096/fj.14-252411
    tissue_or_cell_type
    Inner mitochondrial membrane

    Lutein: metabolism, signaling and nutrient connections (2026-09-17) · lines 307–318

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Subcellular localization and mitochondrial fractionation · source_derived_draft · unverified_draft

    ### lutein-bco2-inner-membrane Human BCO2 associated with the inner mitochondrial membrane in cell-line experiments. Condition category: normal nutrient_topic: Lutein research collection; topical membership is not evidence of a direct dietary effect. plain_language: Carotenoid breakdown is organized within a particular compartment. organism: Human isoforms in cell lines and mouse liver tissue_or_cell_type: Inner mitochondrial membrane experimental_model: Subcellular localization and mitochondrial fractionation limitations: Human cell localization and mouse organelle fractionation are separate evidence components. exposure: Cleavable N-terminal leaders and compartment analyses evidence_span: {"source_cache": "artifacts/lutein-research/25002123.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "13eecc413b623871f99140525333718bec180923ca6673fab15a9dee19a0551b", "start_char": 0, "end_char": 1308, "text_sha256": "13eecc413b623871f99140525333718bec180923ca6673fab15a9dee19a0551b"} [lutein-p25002123] Evidence for compartmentalization of mammalian carotenoid metabolism. (2014). https://pubmed.ncbi.nlm.nih.gov/25002123/ DOI: 10.1096/fj.14-252411
    Complete structured claim and evidence

  5. Human donor retina had higher BCO2 protein expression peripherally than centrally.

    Human beta-carotene oxygenase 2 / BCO2 → Human retinal BCO2 regional protein abundance source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/lutein-research/39978586.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3546acef9586e54733ec1f03797741c67643606de59f80a7762815b32c3c03fe", "start_char": 0, "end_char": 1561, "text_sha256": "3546acef9586e54733ec1f03797741c67643606de59f80a7762815b32c3c03fe"}
    experimental_model
    Validated antibodies, localization, donor-retina analysis and activity assays
    exposure
    BCO2 precursor/processed protein comparison; Aster interactions
    limitations
    Protein expression and interaction evidence does not by itself quantify lutein cleavage in living human retina.
    nutrient_topic
    Lutein research collection; topical membership is not evidence of a direct dietary effect. · Lutein
    organism
    Human cells/donor retina and macaque retina
    plain_language
    The breakdown enzyme was unevenly distributed across the retina.
    primary_references
    [lutein-p39978586] Unveiling BCO2 function in macular pigment metabolism: Mitochondrial processing and expression in the primate retina. (2025). https://pubmed.ncbi.nlm.nih.gov/39978586/ DOI: 10.1016/j.bbalip.2025.159600
    tissue_or_cell_type
    Retinal regions and mitochondria

    Lutein: metabolism, signaling and nutrient connections (2026-09-17) · lines 333–344

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Validated antibodies, localization, donor-retina analysis and activity assays · source_derived_draft · unverified_draft

    ### lutein-bco2-regional Human donor retina had higher BCO2 protein expression peripherally than centrally. Condition category: normal nutrient_topic: Lutein research collection; topical membership is not evidence of a direct dietary effect. plain_language: The breakdown enzyme was unevenly distributed across the retina. organism: Human cells/donor retina and macaque retina tissue_or_cell_type: Retinal regions and mitochondria experimental_model: Validated antibodies, localization, donor-retina analysis and activity assays limitations: Protein expression and interaction evidence does not by itself quantify lutein cleavage in living human retina. exposure: BCO2 precursor/processed protein comparison; Aster interactions evidence_span: {"source_cache": "artifacts/lutein-research/39978586.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3546acef9586e54733ec1f03797741c67643606de59f80a7762815b32c3c03fe", "start_char": 0, "end_char": 1561, "text_sha256": "3546acef9586e54733ec1f03797741c67643606de59f80a7762815b32c3c03fe"} [lutein-p39978586] Unveiling BCO2 function in macular pigment metabolism: Mitochondrial processing and expression in the primate retina. (2025). https://pubmed.ncbi.nlm.nih.gov/39978586/ DOI: 10.1016/j.bbalip.2025.159600
    Complete structured claim and evidence

  6. The 2024 study reported greater BCO2 expression in the macular region than peripherally.

    Human beta-carotene oxygenase 2 / BCO2 → Human retinal BCO2 regional protein abundance source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/zeaxanthin-research/39151780.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e43805b4445f15c3f6490ab163d908ee7a43f475538b3160fc1ea9771cff9ab4", "start_char": 0, "end_char": 1282, "text_sha256": "e43805b4445f15c3f6490ab163d908ee7a43f475538b3160fc1ea9771cff9ab4"}
    experimental_model
    Confocal Raman/fluorescence imaging and expression analysis
    exposure
    Twelve carotenoid-related proteins; Western blot and single-cell RNA database
    limitations
    Localization is not proof of transport direction or rate. Regional BCO2 result differs from the 2025 study; antibody specificity, sampling and compartment remain unresolved comparison variables.
    nutrient_topic
    Zeaxanthin research collection; topical membership is not evidence of a direct dietary effect. · Dietary (3R,3-prime-R)-zeaxanthin
    organism
    Human donor retina and RPE
    plain_language
    This paper placed more BCO2 centrally.
    primary_references
    [zeaxanthin-p39151780] Imaging macular carotenoids and their related proteins in the human retina with confocal resonance Raman and fluorescence microscopy. (2024). https://pubmed.ncbi.nlm.nih.gov/39151780/ DOI: 10.1016/j.exer.2024.110043
    tissue_or_cell_type
    Central versus peripheral retinal regions

    Zeaxanthin: metabolism, signaling and nutrient connections (2026-09-17) · lines 561–572

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Confocal Raman/fluorescence imaging and expression analysis · source_derived_draft · unverified_draft

    ### zeaxanthin-bco2-central-2024 The 2024 study reported greater BCO2 expression in the macular region than peripherally. Condition category: normal nutrient_topic: Zeaxanthin research collection; topical membership is not evidence of a direct dietary effect. plain_language: This paper placed more BCO2 centrally. organism: Human donor retina and RPE tissue_or_cell_type: Central versus peripheral retinal regions experimental_model: Confocal Raman/fluorescence imaging and expression analysis limitations: Localization is not proof of transport direction or rate. Regional BCO2 result differs from the 2025 study; antibody specificity, sampling and compartment remain unresolved comparison variables. exposure: Twelve carotenoid-related proteins; Western blot and single-cell RNA database evidence_span: {"source_cache": "artifacts/zeaxanthin-research/39151780.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e43805b4445f15c3f6490ab163d908ee7a43f475538b3160fc1ea9771cff9ab4", "start_char": 0, "end_char": 1282, "text_sha256": "e43805b4445f15c3f6490ab163d908ee7a43f475538b3160fc1ea9771cff9ab4"} [zeaxanthin-p39151780] Imaging macular carotenoids and their related proteins in the human retina with confocal resonance Raman and fluorescence microscopy. (2024). https://pubmed.ncbi.nlm.nih.gov/39151780/ DOI: 10.1016/j.exer.2024.110043
    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