Component

Rat thioredoxin reductase 1 / Txnrd1

Rattus norvegicus cytosolic thioredoxin reductase, distinct from the canonical human TXNRD1 node.

14 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. A rat TXNRD1 structure and docking model with human thioredoxin support a relay through the opposite subunit and C-terminal tail toward the substrate.

    Rat thioredoxin reductase 1 / Txnrd1 → TXN1 source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    B2-dependent electron input and selenium-containing terminal chemistry are separate serial steps.
    evidence_location
    Abstract
    experimental_model
    Rat TXNRD1 Sec498Cys recombinant mutant with NADP+, 3.0-A crystallography and substrate-docking interpretation.
    exposure
    Purified-enzyme assay
    limitations
    Human thioredoxin was docked onto the rat Sec498Cys structure (Fig 6); the complex and cross-species turnover were not measured.
    nutrient_topic
    Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
    organism
    Rattus norvegicus reductase and Homo sapiens thioredoxin docking partner
    plain_language
    A second redox center carries electrons onward to thioredoxin.
    primary_references
    [sandalova2001] Three-dimensional structure of a mammalian thioredoxin reductase: implications for mechanism and evolution of a selenocysteine-dependent enzyme. (2001). https://pubmed.ncbi.nlm.nih.gov/11481439/ DOI: 10.1073/pnas.171178698
    tissue_or_cell_type
    Purified recombinant enzyme; no intact tissue

    Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1360–1372

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Rat TXNRD1 Sec498Cys recombinant mutant with NADP+, 3.0-A crystallography and substrate-docking interpretation. · source_derived_draft · unverified_draft

    ### b2-txnrd1-terminal-relay A rat TXNRD1 structure and docking model with human thioredoxin support a relay through the opposite subunit and C-terminal tail toward the substrate. Condition category: normal nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: A second redox center carries electrons onward to thioredoxin. organism: Rattus norvegicus reductase and Homo sapiens thioredoxin docking partner tissue_or_cell_type: Purified recombinant enzyme; no intact tissue experimental_model: Rat TXNRD1 Sec498Cys recombinant mutant with NADP+, 3.0-A crystallography and substrate-docking interpretation. limitations: Human thioredoxin was docked onto the rat Sec498Cys structure (Fig 6); the complex and cross-species turnover were not measured. exposure: Purified-enzyme assay cross_nutrient: B2-dependent electron input and selenium-containing terminal chemistry are separate serial steps. evidence_location: Abstract [sandalova2001] Three-dimensional structure of a mammalian thioredoxin reductase: implications for mechanism and evolution of a selenocysteine-dependent enzyme. (2001). https://pubmed.ncbi.nlm.nih.gov/11481439/ DOI: 10.1073/pnas.171178698
    Complete structured claim and evidence

  2. Purified rat liver thioredoxin reductase reduced DHA using NADPH, with apparent DHA Km 2.5 mM and turnover 90 min−1.

    Rat thioredoxin reductase 1 / Txnrd1 → Dehydroascorbic acid source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    true
    experimental_model
    Purified rat liver thioredoxin reductase/thioredoxin and selenium-deficient rat liver
    exposure
    Purified enzyme plus NADPH and DHA
    limitations
    Biochemical capacity; not the same as cellular rate at low DHA concentration.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Rattus norvegicus
    plain_language
    Thioredoxin reductase provides another route for recovering reduced vitamin C.
    primary_references
    [may1997] Reduction of dehydroascorbate to ascorbate by the selenoenzyme thioredoxin reductase. (1997). https://pubmed.ncbi.nlm.nih.gov/9278416/ DOI: 10.1074/jbc.272.36.22607
    tissue_or_cell_type
    Purified liver enzyme

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 377–388

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat liver thioredoxin reductase/thioredoxin and selenium-deficient rat liver · source_derived_draft · unverified_draft

    ### vc-transport-txnrd-dha Purified rat liver thioredoxin reductase reduced DHA using NADPH, with apparent DHA Km 2.5 mM and turnover 90 min−1. Condition category: normal nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: Thioredoxin reductase provides another route for recovering reduced vitamin C. organism: Rattus norvegicus tissue_or_cell_type: Purified liver enzyme experimental_model: Purified rat liver thioredoxin reductase/thioredoxin and selenium-deficient rat liver limitations: Biochemical capacity; not the same as cellular rate at low DHA concentration. exposure: Purified enzyme plus NADPH and DHA cross_nutrient: true [may1997] Reduction of dehydroascorbate to ascorbate by the selenoenzyme thioredoxin reductase. (1997). https://pubmed.ncbi.nlm.nih.gov/9278416/ DOI: 10.1074/jbc.272.36.22607
    Complete structured claim and evidence

  3. Purified rat liver thioredoxin reductase decreased ascorbyl radical measured by electron paramagnetic resonance while consuming NADPH; DHA controls could not explain the signal.

    Rat thioredoxin reductase 1 / Txnrd1 → Ascorbyl radical source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    true
    experimental_model
    Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats
    exposure
    Low-micromolar ascorbyl radical generated by ascorbate oxidase
    limitations
    Purified assay; radical and DHA reduction are distinct reactions.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Rattus norvegicus
    plain_language
    The reductase can also recycle the one-electron vitamin C radical.
    primary_references
    [may1998] Reduction of the ascorbyl free radical to ascorbate by thioredoxin reductase. (1998). https://pubmed.ncbi.nlm.nih.gov/9722529/ DOI: 10.1074/jbc.273.36.23039
    tissue_or_cell_type
    Purified liver enzyme

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 416–427

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats · source_derived_draft · unverified_draft

    ### vc-transport-txnrd-radical Purified rat liver thioredoxin reductase decreased ascorbyl radical measured by electron paramagnetic resonance while consuming NADPH; DHA controls could not explain the signal. Condition category: normal nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: The reductase can also recycle the one-electron vitamin C radical. organism: Rattus norvegicus tissue_or_cell_type: Purified liver enzyme experimental_model: Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats limitations: Purified assay; radical and DHA reduction are distinct reactions. exposure: Low-micromolar ascorbyl radical generated by ascorbate oxidase cross_nutrient: true [may1998] Reduction of the ascorbyl free radical to ascorbate by thioredoxin reductase. (1998). https://pubmed.ncbi.nlm.nih.gov/9722529/ DOI: 10.1074/jbc.273.36.23039
    Complete structured claim and evidence

What acts on it

  1. Curcumin inhibited NADPH-reduced rat TrxR1 and inhibition persisted after curcumin removal.

    Curcumin → Rat thioredoxin reductase 1 / Txnrd1 source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/curcumin-research/15879598.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c", "start_char": 0, "end_char": 1659, "text_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c"}
    experimental_model
    Purified rat enzyme and separate HeLa-cell assays
    exposure
    Rat enzyme: two-hour incubation, IC50 3.6 micromolar; HeLa activity IC50 about 15 micromolar
    limitations
    Rat residue numbering Cys496/Sec497 is source-specific and must not replace numbering in other TrxR constructs. Cellular enzyme activity does not prove clinical cancer benefit.
    nutrient_topic
    Curcumin research collection; topical membership is not evidence of a direct dietary effect. · Curcumin
    organism
    Rattus norvegicus
    plain_language
    An enzyme that normally helps control oxidation was inhibited.
    primary_references
    [curcumin-p15879598] Thioredoxin reductase is irreversibly modified by curcumin: a novel molecular mechanism for its anticancer activity. (2005). https://pubmed.ncbi.nlm.nih.gov/15879598/ DOI: 10.1074/jbc.m414645200
    tissue_or_cell_type
    Purified enzyme

    Curcumin: metabolism, signaling and nutrient connections (2026-09-17) · lines 502–513

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat enzyme and separate HeLa-cell assays · source_derived_draft · unverified_draft

    ### curcumin-trx-inhibition Curcumin inhibited NADPH-reduced rat TrxR1 and inhibition persisted after curcumin removal. Condition category: normal nutrient_topic: Curcumin research collection; topical membership is not evidence of a direct dietary effect. plain_language: An enzyme that normally helps control oxidation was inhibited. organism: Rattus norvegicus tissue_or_cell_type: Purified enzyme experimental_model: Purified rat enzyme and separate HeLa-cell assays limitations: Rat residue numbering Cys496/Sec497 is source-specific and must not replace numbering in other TrxR constructs. Cellular enzyme activity does not prove clinical cancer benefit. exposure: Rat enzyme: two-hour incubation, IC50 3.6 micromolar; HeLa activity IC50 about 15 micromolar evidence_span: {"source_cache": "artifacts/curcumin-research/15879598.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c", "start_char": 0, "end_char": 1659, "text_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c"} [curcumin-p15879598] Thioredoxin reductase is irreversibly modified by curcumin: a novel molecular mechanism for its anticancer activity. (2005). https://pubmed.ncbi.nlm.nih.gov/15879598/ DOI: 10.1074/jbc.m414645200
    Complete structured claim and evidence

  2. The rat TXNRD1 Sec498Cys structure showed conserved FAD- and NADPH-binding architecture around the N-terminal redox center.

    FAD → Rat thioredoxin reductase 1 / Txnrd1 source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    B2-FAD and nicotinamide cofactors provide the upstream side of a selenium-containing reductase.
    evidence_location
    Abstract
    experimental_model
    Rat TXNRD1 Sec498Cys recombinant mutant with NADP+, 3.0-A crystallography and substrate-docking interpretation.
    exposure
    Purified-enzyme assay
    limitations
    Structure used a Sec-to-Cys mutant and oxidized NADP+; direct atom-level conclusions about wild-type selenium chemistry are limited.
    nutrient_topic
    Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
    organism
    Rattus norvegicus protein expressed recombinantly
    plain_language
    Thioredoxin reductase has a flavin input side.
    primary_references
    [sandalova2001] Three-dimensional structure of a mammalian thioredoxin reductase: implications for mechanism and evolution of a selenocysteine-dependent enzyme. (2001). https://pubmed.ncbi.nlm.nih.gov/11481439/ DOI: 10.1073/pnas.171178698
    tissue_or_cell_type
    Purified recombinant enzyme; no intact tissue

    Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1346–1358

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Rat TXNRD1 Sec498Cys recombinant mutant with NADP+, 3.0-A crystallography and substrate-docking interpretation. · source_derived_draft · unverified_draft

    ### b2-txnrd1-fad-nadph-architecture The rat TXNRD1 Sec498Cys structure showed conserved FAD- and NADPH-binding architecture around the N-terminal redox center. Condition category: normal nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Thioredoxin reductase has a flavin input side. organism: Rattus norvegicus protein expressed recombinantly tissue_or_cell_type: Purified recombinant enzyme; no intact tissue experimental_model: Rat TXNRD1 Sec498Cys recombinant mutant with NADP+, 3.0-A crystallography and substrate-docking interpretation. limitations: Structure used a Sec-to-Cys mutant and oxidized NADP+; direct atom-level conclusions about wild-type selenium chemistry are limited. exposure: Purified-enzyme assay cross_nutrient: B2-FAD and nicotinamide cofactors provide the upstream side of a selenium-containing reductase. evidence_location: Abstract [sandalova2001] Three-dimensional structure of a mammalian thioredoxin reductase: implications for mechanism and evolution of a selenocysteine-dependent enzyme. (2001). https://pubmed.ncbi.nlm.nih.gov/11481439/ DOI: 10.1073/pnas.171178698
    Complete structured claim and evidence

  3. Myricetin inhibition was time- and NADPH-dependent and involved the reduced C-terminal Cys-Sec-Gly active site.

    Myricetin → Rat thioredoxin reductase 1 / Txnrd1 source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract and publisher methods/results
    experimental_model
    Rat TrxR biochemical experiments.
    limitations
    Semiquinone mediation was proposed; do not treat the precise intermediate as directly proven.
    nutrient_topic
    Myricetin collection; molecular form, preparation, species, exposure and manipulation remain explicit. · Myricetin
    plain_language
    The enzyme’s chemical state affects vulnerability.
    primary_references
    Inhibition of Mammalian thioredoxin reductase by some flavonoids: implications for myricetin and quercetin anticancer activity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16618767/ · DOI 10.1158/0008-5472.CAN-05-3310

    Myricetin: metabolism, immune signaling, redox chemistry and cross-nutrient mechanisms (2026-09-19) · lines 260–266

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Rat TrxR biochemical experiments. · source_derived_draft · unverified_draft

    ## myricetin-txnrd-active-site The enzyme’s chemical state affects vulnerability. Myricetin inhibition was time- and NADPH-dependent and involved the reduced C-terminal Cys-Sec-Gly active site. Model: Rat TrxR biochemical experiments. Limitations: Semiquinone mediation was proposed; do not treat the precise intermediate as directly proven. Evidence access: Primary abstract and publisher methods/results Inhibition of Mammalian thioredoxin reductase by some flavonoids: implications for myricetin and quercetin anticancer activity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16618767/ · DOI 10.1158/0008-5472.CAN-05-3310
    Complete structured claim and evidence

  4. Myricetin inhibited NADPH-reduced recombinant rat TrxR1, IC50 0.62 micromolar after the reported preincubation.

    Myricetin → Rat thioredoxin reductase 1 / Txnrd1 source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract and publisher methods/results
    experimental_model
    Recombinant rat TrxR; one-hour preincubation and DTNB assay.
    limitations
    Enzyme potency differs from cellular exposure; not human dietary selenium depletion.
    nutrient_topic
    Myricetin collection; molecular form, preparation, species, exposure and manipulation remain explicit. · Myricetin
    plain_language
    A selenium-containing defense enzyme can be inhibited.
    primary_references
    Inhibition of Mammalian thioredoxin reductase by some flavonoids: implications for myricetin and quercetin anticancer activity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16618767/ · DOI 10.1158/0008-5472.CAN-05-3310

    Myricetin: metabolism, immune signaling, redox chemistry and cross-nutrient mechanisms (2026-09-19) · lines 252–258

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Recombinant rat TrxR; one-hour preincubation and DTNB assay. · source_derived_draft · unverified_draft

    ## myricetin-txnrd-inhibition A selenium-containing defense enzyme can be inhibited. Myricetin inhibited NADPH-reduced recombinant rat TrxR1, IC50 0.62 micromolar after the reported preincubation. Model: Recombinant rat TrxR; one-hour preincubation and DTNB assay. Limitations: Enzyme potency differs from cellular exposure; not human dietary selenium depletion. Evidence access: Primary abstract and publisher methods/results Inhibition of Mammalian thioredoxin reductase by some flavonoids: implications for myricetin and quercetin anticancer activity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16618767/ · DOI 10.1158/0008-5472.CAN-05-3310
    Complete structured claim and evidence

  5. Superoxide enhanced myricetin-mediated TrxR inhibition, while anaerobic conditions attenuated it.

    Superoxide radical anion → Rat thioredoxin reductase 1 / Txnrd1 source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract and publisher methods/results
    experimental_model
    Cell-free mammalian TrxR study.
    limitations
    This does not show that lowering oxygen or adding antioxidants benefits patients.
    nutrient_topic
    Myricetin collection; molecular form, preparation, species, exposure and manipulation remain explicit. · Myricetin
    plain_language
    Oxygen chemistry changes the inhibitory response.
    primary_references
    Inhibition of Mammalian thioredoxin reductase by some flavonoids: implications for myricetin and quercetin anticancer activity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16618767/ · DOI 10.1158/0008-5472.CAN-05-3310

    Myricetin: metabolism, immune signaling, redox chemistry and cross-nutrient mechanisms (2026-09-19) · lines 268–274

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Cell-free mammalian TrxR study. · source_derived_draft · unverified_draft

    ## myricetin-txnrd-oxygen Oxygen chemistry changes the inhibitory response. Superoxide enhanced myricetin-mediated TrxR inhibition, while anaerobic conditions attenuated it. Model: Cell-free mammalian TrxR study. Limitations: This does not show that lowering oxygen or adding antioxidants benefits patients. Evidence access: Primary abstract and publisher methods/results Inhibition of Mammalian thioredoxin reductase by some flavonoids: implications for myricetin and quercetin anticancer activity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16618767/ · DOI 10.1158/0008-5472.CAN-05-3310
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Mass spectrometry and blotting supported modification of Cys496 and Sec497 in the rat enzyme.

    Curcumin → Curcumin-modified rat thioredoxin reductase 1 source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/curcumin-research/15879598.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c", "start_char": 0, "end_char": 1659, "text_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c"}
    experimental_model
    Purified rat enzyme and separate HeLa-cell assays
    exposure
    Rat enzyme: two-hour incubation, IC50 3.6 micromolar; HeLa activity IC50 about 15 micromolar
    limitations
    Rat residue numbering Cys496/Sec497 is source-specific and must not replace numbering in other TrxR constructs. Cellular enzyme activity does not prove clinical cancer benefit.
    nutrient_topic
    Curcumin research collection; topical membership is not evidence of a direct dietary effect. · Curcumin
    organism
    Rattus norvegicus
    plain_language
    The interaction included the selenium-containing active-site residue.
    primary_references
    [curcumin-p15879598] Thioredoxin reductase is irreversibly modified by curcumin: a novel molecular mechanism for its anticancer activity. (2005). https://pubmed.ncbi.nlm.nih.gov/15879598/ DOI: 10.1074/jbc.m414645200
    tissue_or_cell_type
    Purified enzyme

    Curcumin: metabolism, signaling and nutrient connections (2026-09-17) · lines 515–526

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat enzyme and separate HeLa-cell assays · source_derived_draft · unverified_draft

    ### curcumin-trx-adduct Mass spectrometry and blotting supported modification of Cys496 and Sec497 in the rat enzyme. Condition category: normal nutrient_topic: Curcumin research collection; topical membership is not evidence of a direct dietary effect. plain_language: The interaction included the selenium-containing active-site residue. organism: Rattus norvegicus tissue_or_cell_type: Purified enzyme experimental_model: Purified rat enzyme and separate HeLa-cell assays limitations: Rat residue numbering Cys496/Sec497 is source-specific and must not replace numbering in other TrxR constructs. Cellular enzyme activity does not prove clinical cancer benefit. exposure: Rat enzyme: two-hour incubation, IC50 3.6 micromolar; HeLa activity IC50 about 15 micromolar evidence_span: {"source_cache": "artifacts/curcumin-research/15879598.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c", "start_char": 0, "end_char": 1659, "text_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c"} [curcumin-p15879598] Thioredoxin reductase is irreversibly modified by curcumin: a novel molecular mechanism for its anticancer activity. (2005). https://pubmed.ncbi.nlm.nih.gov/15879598/ DOI: 10.1074/jbc.m414645200
    Complete structured claim and evidence

  2. The modified enzyme acquired increased NADPH oxidase activity associated with reactive oxygen species production.

    Curcumin-modified rat thioredoxin reductase 1 → NADPH oxidase activity of curcumin-modified rat TrxR1 source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/curcumin-research/15879598.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c", "start_char": 0, "end_char": 1659, "text_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c"}
    experimental_model
    Purified rat enzyme and separate HeLa-cell assays
    exposure
    Rat enzyme: two-hour incubation, IC50 3.6 micromolar; HeLa activity IC50 about 15 micromolar
    limitations
    Rat residue numbering Cys496/Sec497 is source-specific and must not replace numbering in other TrxR constructs. Cellular enzyme activity does not prove clinical cancer benefit.
    nutrient_topic
    Curcumin research collection; topical membership is not evidence of a direct dietary effect. · Curcumin
    organism
    Rattus norvegicus
    plain_language
    The modified protein could consume reducing power while promoting oxidation.
    primary_references
    [curcumin-p15879598] Thioredoxin reductase is irreversibly modified by curcumin: a novel molecular mechanism for its anticancer activity. (2005). https://pubmed.ncbi.nlm.nih.gov/15879598/ DOI: 10.1074/jbc.m414645200
    tissue_or_cell_type
    Purified enzyme

    Curcumin: metabolism, signaling and nutrient connections (2026-09-17) · lines 528–539

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat enzyme and separate HeLa-cell assays · source_derived_draft · unverified_draft

    ### curcumin-trx-oxidase The modified enzyme acquired increased NADPH oxidase activity associated with reactive oxygen species production. Condition category: normal nutrient_topic: Curcumin research collection; topical membership is not evidence of a direct dietary effect. plain_language: The modified protein could consume reducing power while promoting oxidation. organism: Rattus norvegicus tissue_or_cell_type: Purified enzyme experimental_model: Purified rat enzyme and separate HeLa-cell assays limitations: Rat residue numbering Cys496/Sec497 is source-specific and must not replace numbering in other TrxR constructs. Cellular enzyme activity does not prove clinical cancer benefit. exposure: Rat enzyme: two-hour incubation, IC50 3.6 micromolar; HeLa activity IC50 about 15 micromolar evidence_span: {"source_cache": "artifacts/curcumin-research/15879598.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c", "start_char": 0, "end_char": 1659, "text_sha256": "be68f9ed2b0741db356a6bc020304fe832121f92dfd9c423ce8a305e984e995c"} [curcumin-p15879598] Thioredoxin reductase is irreversibly modified by curcumin: a novel molecular mechanism for its anticancer activity. (2005). https://pubmed.ncbi.nlm.nih.gov/15879598/ DOI: 10.1074/jbc.m414645200
    Complete structured claim and evidence

  3. Engineered rat TXNRD1 terminal mutants retained one FAD per subunit and rapidly formed a thiolate-flavin charge-transfer signal upon NADPH titration.

    Rat TXNRD1 Sec498Cys protein → FAD source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    cross_nutrient
    Distinct B2-cofactor and selenium-site functions cannot substitute for one another.
    evidence_location
    Abstract
    experimental_model
    Rat TXNRD1 Sec498Cys, Sec498Ser and C-terminal truncation expressed in E. coli; FAD analysis, NADPH titration and thioredoxin assays.
    exposure
    Purified-enzyme assay
    limitations
    Includes Sec498Cys, Sec498Ser and terminal truncation; engineered proteins, not nutrient-depleted animals.
    nutrient_topic
    Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
    organism
    Rattus norvegicus protein expressed in Escherichia coli
    plain_language
    A defective terminal center can leave upstream flavin reduction intact.
    primary_references
    [zhong2000] Essential role of selenium in the catalytic activities of mammalian thioredoxin reductase revealed by characterization of recombinant enzymes with selenocysteine mutations. (2000). https://pubmed.ncbi.nlm.nih.gov/10849437/ DOI: 10.1074/jbc.m000690200
    tissue_or_cell_type
    Purified recombinant enzyme; no intact tissue
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1374–1386

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Rat TXNRD1 Sec498Cys, Sec498Ser and C-terminal truncation expressed in E. coli; FAD analysis, NADPH titration and thioredoxin assays. · source_derived_draft · unverified_draft

    ### b2-txnrd-mutants-upstream-retained Engineered rat TXNRD1 terminal mutants retained one FAD per subunit and rapidly formed a thiolate-flavin charge-transfer signal upon NADPH titration. Condition category: machinery_impairment nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: A defective terminal center can leave upstream flavin reduction intact. organism: Rattus norvegicus protein expressed in Escherichia coli tissue_or_cell_type: Purified recombinant enzyme; no intact tissue experimental_model: Rat TXNRD1 Sec498Cys, Sec498Ser and C-terminal truncation expressed in E. coli; FAD analysis, NADPH titration and thioredoxin assays. limitations: Includes Sec498Cys, Sec498Ser and terminal truncation; engineered proteins, not nutrient-depleted animals. exposure: Purified-enzyme assay cross_nutrient: Distinct B2-cofactor and selenium-site functions cannot substitute for one another. evidence_location: Abstract [zhong2000] Essential role of selenium in the catalytic activities of mammalian thioredoxin reductase revealed by characterization of recombinant enzymes with selenocysteine mutations. (2000). https://pubmed.ncbi.nlm.nih.gov/10849437/ DOI: 10.1074/jbc.m000690200
    Complete structured claim and evidence

  4. Dialyzed liver cytosol from selenium-deficient rats lost NADPH-dependent ascorbyl-radical reducing activity attributed to thioredoxin reductase.

    Selenium → Ascorbyl radical reduction to ascorbate source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    true
    experimental_model
    Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats
    exposure
    Dietary selenium depletion; isolated dialyzed cytosol
    limitations
    Activity assignment also used inhibitor sensitivity; this is a fraction assay, not a direct human outcome.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Rattus norvegicus
    plain_language
    Selenium deficiency impaired radical recycling in the rat liver’s soluble fraction.
    primary_references
    [may1998] Reduction of the ascorbyl free radical to ascorbate by thioredoxin reductase. (1998). https://pubmed.ncbi.nlm.nih.gov/9722529/ DOI: 10.1074/jbc.273.36.23039
    tissue_or_cell_type
    Liver cytosol
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 429–440

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats · source_derived_draft · unverified_draft

    ### vc-transport-selenium-cytosolic-radical Dialyzed liver cytosol from selenium-deficient rats lost NADPH-dependent ascorbyl-radical reducing activity attributed to thioredoxin reductase. Condition category: nutrient_deficiency nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: Selenium deficiency impaired radical recycling in the rat liver’s soluble fraction. organism: Rattus norvegicus tissue_or_cell_type: Liver cytosol experimental_model: Purified rat liver enzyme, dialyzed cytosol and microsomes from control/selenium-deficient rats limitations: Activity assignment also used inhibitor sensitivity; this is a fraction assay, not a direct human outcome. exposure: Dietary selenium depletion; isolated dialyzed cytosol cross_nutrient: true [may1998] Reduction of the ascorbyl free radical to ascorbate by thioredoxin reductase. (1998). https://pubmed.ncbi.nlm.nih.gov/9722529/ DOI: 10.1074/jbc.273.36.23039
    Complete structured claim and evidence

  5. Selenium-deficient rats had 33% less liver ascorbate together with an 88% fall in thioredoxin-reductase activity; liver GSH content was unchanged.

    Selenium → Liver ascorbate content source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    true
    experimental_model
    Purified rat liver thioredoxin reductase/thioredoxin and selenium-deficient rat liver
    exposure
    Dietary selenium deficiency
    limitations
    Several selenoenzymes were affected, including glutathione peroxidase; cannot attribute the entire ascorbate decrease solely to thioredoxin reductase.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Rattus norvegicus
    plain_language
    Selenium shortage reduced a vitamin C recycling pathway and liver vitamin C in rats.
    primary_references
    [may1997] Reduction of dehydroascorbate to ascorbate by the selenoenzyme thioredoxin reductase. (1997). https://pubmed.ncbi.nlm.nih.gov/9278416/ DOI: 10.1074/jbc.272.36.22607
    tissue_or_cell_type
    Liver
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 403–414

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat liver thioredoxin reductase/thioredoxin and selenium-deficient rat liver · source_derived_draft · unverified_draft

    ### vc-transport-selenium-liver-ascorbate Selenium-deficient rats had 33% less liver ascorbate together with an 88% fall in thioredoxin-reductase activity; liver GSH content was unchanged. Condition category: nutrient_deficiency nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: Selenium shortage reduced a vitamin C recycling pathway and liver vitamin C in rats. organism: Rattus norvegicus tissue_or_cell_type: Liver experimental_model: Purified rat liver thioredoxin reductase/thioredoxin and selenium-deficient rat liver limitations: Several selenoenzymes were affected, including glutathione peroxidase; cannot attribute the entire ascorbate decrease solely to thioredoxin reductase. exposure: Dietary selenium deficiency cross_nutrient: true [may1997] Reduction of dehydroascorbate to ascorbate by the selenoenzyme thioredoxin reductase. (1997). https://pubmed.ncbi.nlm.nih.gov/9278416/ DOI: 10.1074/jbc.272.36.22607
    Complete structured claim and evidence

  6. Adding 2.8 µM rat liver thioredoxin lowered apparent DHA Km of the thioredoxin-reductase system from 2.5 to 0.7 mM without materially increasing turnover.

    Rat thioredoxin 1 / Txn1 → Dehydroascorbic acid reduction to ascorbate source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    true
    experimental_model
    Purified rat liver thioredoxin reductase/thioredoxin and selenium-deficient rat liver
    exposure
    2.8 µM thioredoxin added to NADPH/thioredoxin-reductase assay
    limitations
    Apparent kinetic effect is not proof of a faster whole-body recycling rate.
    nutrient_topic
    Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
    organism
    Rattus norvegicus
    plain_language
    Thioredoxin improved the system’s apparent affinity for oxidized vitamin C in this assay.
    primary_references
    [may1997] Reduction of dehydroascorbate to ascorbate by the selenoenzyme thioredoxin reductase. (1997). https://pubmed.ncbi.nlm.nih.gov/9278416/ DOI: 10.1074/jbc.272.36.22607
    tissue_or_cell_type
    Purified liver enzymes

    Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 390–401

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat liver thioredoxin reductase/thioredoxin and selenium-deficient rat liver · source_derived_draft · unverified_draft

    ### vc-transport-thioredoxin-dha-affinity Adding 2.8 µM rat liver thioredoxin lowered apparent DHA Km of the thioredoxin-reductase system from 2.5 to 0.7 mM without materially increasing turnover. Condition category: normal nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: Thioredoxin improved the system’s apparent affinity for oxidized vitamin C in this assay. organism: Rattus norvegicus tissue_or_cell_type: Purified liver enzymes experimental_model: Purified rat liver thioredoxin reductase/thioredoxin and selenium-deficient rat liver limitations: Apparent kinetic effect is not proof of a faster whole-body recycling rate. exposure: 2.8 µM thioredoxin added to NADPH/thioredoxin-reductase assay cross_nutrient: true [may1997] Reduction of dehydroascorbate to ascorbate by the selenoenzyme thioredoxin reductase. (1997). https://pubmed.ncbi.nlm.nih.gov/9278416/ DOI: 10.1074/jbc.272.36.22607
    Complete structured claim and evidence

In the sources

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    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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