Component

GCH1

Independent biological entity. Read linked claims for experimental scope and context.

4 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 GFRP enabled phenylalanine-dependent stimulation of recombinant human GCH1.

    L-Phenylalanine → GCH1 source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Recombinant human proteins; primary abstract.
    limitations
    GCH1 controls an early BH4-biosynthesis step; this is not proof that supplemental phenylalanine raises BH4 in every tissue.
    nutrient_topic
    L-Phenylalanine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Phenylalanine
    plain_language
    The substrate can signal for more of the cofactor-making machinery to work.
    primary_references
    Bacterial lipopolysaccharide down-regulates expression of GTP cyclohydrolase I feedback regulatory protein. · 2002 · https://pubmed.ncbi.nlm.nih.gov/11799107/ · DOI 10.1074/jbc.M107326200

    L-Phenylalanine: transport, protein synthesis, cofactor recycling and cross-nutrient mechanisms (2026-09-19) · lines 38–44

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Recombinant human proteins; primary abstract. · source_derived_draft · unverified_draft

    ## l-phenylalanine-gch1-feedforward The substrate can signal for more of the cofactor-making machinery to work. Recombinant human GFRP enabled phenylalanine-dependent stimulation of recombinant human GCH1. Model: Recombinant human proteins; primary abstract. Limitations: GCH1 controls an early BH4-biosynthesis step; this is not proof that supplemental phenylalanine raises BH4 in every tissue. Evidence access: Primary abstract Bacterial lipopolysaccharide down-regulates expression of GTP cyclohydrolase I feedback regulatory protein. · 2002 · https://pubmed.ncbi.nlm.nih.gov/11799107/ · DOI 10.1074/jbc.M107326200
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. BH4 and phenylalanine favored inhibited and activated human GCH1-GFRP complexes, respectively; ligand-dependent conformational changes stabilized binding.

    Tetrahydrobiopterin / BH4 → Human GTP cyclohydrolase 1 feedback regulatory protein / GCHFR source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Human purified proteins, crystallography and binding/kinetic studies.
    limitations
    Cofactor synthesis has additional steps; structural regulation does not establish a clinical depletion or supplementation effect.
    nutrient_topic
    L-Phenylalanine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Phenylalanine
    plain_language
    Cofactor production has both a demand signal and a feedback brake.
    primary_references
    Biophysical and structural investigation of the regulation of human GTP cyclohydrolase I by its regulatory protein GFRP. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33387654/ · DOI 10.1016/j.jsb.2020.107691

    L-Phenylalanine: transport, protein synthesis, cofactor recycling and cross-nutrient mechanisms (2026-09-19) · lines 46–52

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human purified proteins, crystallography and binding/kinetic studies. · source_derived_draft · unverified_draft

    ## l-phenylalanine-gch1-feedback Cofactor production has both a demand signal and a feedback brake. BH4 and phenylalanine favored inhibited and activated human GCH1-GFRP complexes, respectively; ligand-dependent conformational changes stabilized binding. Model: Human purified proteins, crystallography and binding/kinetic studies. Limitations: Cofactor synthesis has additional steps; structural regulation does not establish a clinical depletion or supplementation effect. Evidence access: Primary abstract Biophysical and structural investigation of the regulation of human GTP cyclohydrolase I by its regulatory protein GFRP. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33387654/ · DOI 10.1016/j.jsb.2020.107691
    Complete structured claim and evidence

  2. LPS at 1 microgram/mL reduced GFRP expression in human THP-1 cells; with interferon-gamma plus LPS, pteridine production became phenylalanine-independent.

    Human GTP cyclohydrolase 1 feedback regulatory protein / GCHFR → THP-1 pteridine response under LPS and interferon-gamma source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Human THP-1 cells; interferon-gamma alone compared with interferon-gamma plus LPS.
    limitations
    Pteridine output is not synonymous with bioavailable BH4; no clinical inflammatory threshold is defined.
    nutrient_topic
    L-Phenylalanine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Phenylalanine
    plain_language
    Inflammatory stimulation changed how this cell model responded to phenylalanine.
    primary_references
    Bacterial lipopolysaccharide down-regulates expression of GTP cyclohydrolase I feedback regulatory protein. · 2002 · https://pubmed.ncbi.nlm.nih.gov/11799107/ · DOI 10.1074/jbc.M107326200

    L-Phenylalanine: transport, protein synthesis, cofactor recycling and cross-nutrient mechanisms (2026-09-19) · lines 54–60

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human THP-1 cells; interferon-gamma alone compared with interferon-gamma plus LPS. · source_derived_draft · unverified_draft

    ## l-phenylalanine-inflammation-feedback Inflammatory stimulation changed how this cell model responded to phenylalanine. LPS at 1 microgram/mL reduced GFRP expression in human THP-1 cells; with interferon-gamma plus LPS, pteridine production became phenylalanine-independent. Model: Human THP-1 cells; interferon-gamma alone compared with interferon-gamma plus LPS. Limitations: Pteridine output is not synonymous with bioavailable BH4; no clinical inflammatory threshold is defined. Evidence access: Primary abstract Bacterial lipopolysaccharide down-regulates expression of GTP cyclohydrolase I feedback regulatory protein. · 2002 · https://pubmed.ncbi.nlm.nih.gov/11799107/ · DOI 10.1074/jbc.M107326200
    Complete structured claim and evidence

  3. ATRA increased GPX4/FSP1 protein and GCH1 transcripts; RAR blockade suppressed the transcript responses.

    All-trans-retinoic acid → GPX4 source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Shared GPX4 connects retinoid signaling to the selenium collection; no proven supplementation synergy.
    experimental_model
    HT-1080 cells; pharmacological ATRA.
    limitations
    Direct promoter binding and dietary selenium replacement were not tested.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Homo sapiens
    plain_language
    Retinoid signaling reached existing ferroptosis-defense machinery.
    primary_references
    [va-berndt2024] Suppression of ferroptosis by vitamin A or radical-trapping antioxidants is essential for neuronal development (2024). https://pubmed.ncbi.nlm.nih.gov/39218970/ DOI: 10.1038/s41467-024-51996-1
    tissue_or_cell_type
    Human cell line

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1811–1821

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · HT-1080 cells; pharmacological ATRA. · source_derived_draft · unverified_draft

    ### va-atra-ferroptosis-regulators ATRA increased GPX4/FSP1 protein and GCH1 transcripts; RAR blockade suppressed the transcript responses. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Retinoid signaling reached existing ferroptosis-defense machinery. organism: Homo sapiens tissue_or_cell_type: Human cell line experimental_model: HT-1080 cells; pharmacological ATRA. limitations: Direct promoter binding and dietary selenium replacement were not tested. cross_nutrient: Shared GPX4 connects retinoid signaling to the selenium collection; no proven supplementation synergy. [va-berndt2024] Suppression of ferroptosis by vitamin A or radical-trapping antioxidants is essential for neuronal development (2024). https://pubmed.ncbi.nlm.nih.gov/39218970/ DOI: 10.1038/s41467-024-51996-1
    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