Component

Human succinate dehydrogenase iron-sulfur subunit / SDHB

Iron-sulfur subunit of human respiratory complex II.

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 it acts on

  1. Human complex II structure and EPR resolved SDHB-associated [2Fe-2S], [4Fe-4S] and [3Fe-4S] redox centers adjacent to its SDHA FAD system.

    Human succinate dehydrogenase iron-sulfur subunit / SDHB → [4Fe-4S] iron-sulfur cluster source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    B2-derived FAD and iron-containing redox centers cooperate within one respiratory complex.
    evidence_spans
    [{"source_bundle": "artifacts/riboflavin_metabolism_sources.json", "source_key": "PMC10161127", "locator": "XML .//body//p", "paragraph_index": 2, "char_start": 0, "char_end": 1105, "evidence_access": "full-text"}]
    experimental_model
    Human complex II purified from HEK293F cells, cryo-EM, EPR and succinate-quinone activity assays.
    exposure
    No nutrient intervention; structural or biochemical characterization.
    limitations
    Structural co-dependence does not show that B2 corrects iron deficiency or that iron supplementation improves this reaction.
    nutrient_topic
    Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
    organism
    Homo sapiens
    plain_language
    Complex II couples a B2-derived flavin with separate iron-sulfur centers.
    primary_references
    [du-2023-human-complex-ii] Structure of the human respiratory complex II (2023). https://pubmed.ncbi.nlm.nih.gov/37098072/ DOI: 10.1073/pnas.2216713120
    tissue_or_cell_type
    HEK293F-derived purified complex II

    Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 649–661

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human complex II purified from HEK293F cells, cryo-EM, EPR and succinate-quinone activity assays. · source_derived_draft · unverified_draft

    ### b2-met-human-sdhb-iron-sulfur Human complex II structure and EPR resolved SDHB-associated [2Fe-2S], [4Fe-4S] and [3Fe-4S] redox centers adjacent to its SDHA FAD system. Condition category: normal nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Complex II couples a B2-derived flavin with separate iron-sulfur centers. organism: Homo sapiens tissue_or_cell_type: HEK293F-derived purified complex II experimental_model: Human complex II purified from HEK293F cells, cryo-EM, EPR and succinate-quinone activity assays. limitations: Structural co-dependence does not show that B2 corrects iron deficiency or that iron supplementation improves this reaction. exposure: No nutrient intervention; structural or biochemical characterization. cross_nutrient: B2-derived FAD and iron-containing redox centers cooperate within one respiratory complex. evidence_spans: [{"source_bundle": "artifacts/riboflavin_metabolism_sources.json", "source_key": "PMC10161127", "locator": "XML .//body//p", "paragraph_index": 2, "char_start": 0, "char_end": 1105, "evidence_access": "full-text"}] [du-2023-human-complex-ii] Structure of the human respiratory complex II (2023). https://pubmed.ncbi.nlm.nih.gov/37098072/ DOI: 10.1073/pnas.2216713120
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Purified human complex II coupled succinate oxidation to ubiquinone reduction in a UQ1/DCIP assay, with reported kcat 0.67 +/- 0.02 per second.

    Respiratory complex II → Ubiquinone-1 source_derived_draftungraded
    Experimental context and source evidence
    evidence_spans
    [{"source_bundle": "artifacts/riboflavin_metabolism_sources.json", "source_key": "PMC10161127", "locator": "XML .//body//p", "paragraph_index": 2, "char_start": 0, "char_end": 1105, "evidence_access": "full-text"}]
    experimental_model
    Human complex II purified from HEK293F cells, cryo-EM, EPR and succinate-quinone activity assays.
    exposure
    No nutrient intervention; structural or biochemical characterization.
    limitations
    UQ1/DCIP are assay reagents; the isolated turnover value is not whole-cell ATP production.
    nutrient_topic
    Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
    organism
    Homo sapiens
    plain_language
    The intact complex moves electrons from succinate into a quinone carrier.
    primary_references
    [du-2023-human-complex-ii] Structure of the human respiratory complex II (2023). https://pubmed.ncbi.nlm.nih.gov/37098072/ DOI: 10.1073/pnas.2216713120
    tissue_or_cell_type
    HEK293F-derived purified complex II

    Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 663–674

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human complex II purified from HEK293F cells, cryo-EM, EPR and succinate-quinone activity assays. · source_derived_draft · unverified_draft

    ### b2-met-human-complex-ii-succinate-quinone Purified human complex II coupled succinate oxidation to ubiquinone reduction in a UQ1/DCIP assay, with reported kcat 0.67 +/- 0.02 per second. Condition category: normal nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: The intact complex moves electrons from succinate into a quinone carrier. organism: Homo sapiens tissue_or_cell_type: HEK293F-derived purified complex II experimental_model: Human complex II purified from HEK293F cells, cryo-EM, EPR and succinate-quinone activity assays. limitations: UQ1/DCIP are assay reagents; the isolated turnover value is not whole-cell ATP production. exposure: No nutrient intervention; structural or biochemical characterization. evidence_spans: [{"source_bundle": "artifacts/riboflavin_metabolism_sources.json", "source_key": "PMC10161127", "locator": "XML .//body//p", "paragraph_index": 2, "char_start": 0, "char_end": 1105, "evidence_access": "full-text"}] [du-2023-human-complex-ii] Structure of the human respiratory complex II (2023). https://pubmed.ncbi.nlm.nih.gov/37098072/ DOI: 10.1073/pnas.2216713120
    Complete structured claim and evidence

  2. SDH inhibition produced early aspartate depletion followed by a rebound, while proliferation remained impaired over the compared interval.

    SDH inhibition or loss in human cell models → Aspartate rebound after SDH inhibition source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_access
    Primary full text
    experimental_model
    Human 143B and other cell models; live aspartate biosensor and time-resolved metabolomics.
    limitations
    Responses are time- and model-dependent; later adaptation does not make the early block disappear.
    nutrient_topic
    L-Aspartate collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Aspartate
    plain_language
    A restored metabolite concentration did not show that the cell could use it normally.
    primary_references
    Succinate dehydrogenase loss suppresses pyrimidine biosynthesis via succinate-mediated inhibition of aspartate transcarbamylase. · 2026 · https://pubmed.ncbi.nlm.nih.gov/42082831/ · DOI 10.1038/s42255-026-01524-w
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    L-Aspartate: redox transfer, nitrogen partitioning and cross-nutrient mechanisms (2026-09-19) · lines 202–208

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human 143B and other cell models; live aspartate biosensor and time-resolved metabolomics. · source_derived_draft · unverified_draft

    ## l-aspartate-sdh-aspartate-rebound A restored metabolite concentration did not show that the cell could use it normally. SDH inhibition produced early aspartate depletion followed by a rebound, while proliferation remained impaired over the compared interval. Model: Human 143B and other cell models; live aspartate biosensor and time-resolved metabolomics. Limitations: Responses are time- and model-dependent; later adaptation does not make the early block disappear. Evidence access: Primary full text Succinate dehydrogenase loss suppresses pyrimidine biosynthesis via succinate-mediated inhibition of aspartate transcarbamylase. · 2026 · https://pubmed.ncbi.nlm.nih.gov/42082831/ · DOI 10.1038/s42255-026-01524-w
    Complete structured claim and evidence

  3. SDH loss increased succinate, impaired aspartate entry into pyrimidine synthesis and produced nucleotide insufficiency with replication stress and increased ATR-inhibitor sensitivity.

    SDH inhibition or loss in human cell models → Pyrimidine production after human-cell SDH impairment source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_access
    Primary full text
    experimental_model
    Human cell genetic/pharmacological SDH perturbations; nucleotide and replication readouts.
    limitations
    Not a clinical treatment recommendation or proof that extra aspartate universally overcomes the competitive block.
    nutrient_topic
    L-Aspartate collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Aspartate
    plain_language
    The effect propagated from metabolism into DNA replication control.
    primary_references
    Succinate dehydrogenase loss suppresses pyrimidine biosynthesis via succinate-mediated inhibition of aspartate transcarbamylase. · 2026 · https://pubmed.ncbi.nlm.nih.gov/42082831/ · DOI 10.1038/s42255-026-01524-w
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    L-Aspartate: redox transfer, nitrogen partitioning and cross-nutrient mechanisms (2026-09-19) · lines 218–224

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human cell genetic/pharmacological SDH perturbations; nucleotide and replication readouts. · source_derived_draft · unverified_draft

    ## l-aspartate-sdh-pyrimidine-stress The effect propagated from metabolism into DNA replication control. SDH loss increased succinate, impaired aspartate entry into pyrimidine synthesis and produced nucleotide insufficiency with replication stress and increased ATR-inhibitor sensitivity. Model: Human cell genetic/pharmacological SDH perturbations; nucleotide and replication readouts. Limitations: Not a clinical treatment recommendation or proof that extra aspartate universally overcomes the competitive block. Evidence access: Primary full text Succinate dehydrogenase loss suppresses pyrimidine biosynthesis via succinate-mediated inhibition of aspartate transcarbamylase. · 2026 · https://pubmed.ncbi.nlm.nih.gov/42082831/ · DOI 10.1038/s42255-026-01524-w
    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