Component

Human transketolase

TKT; thiamine diphosphate-dependent carbon-transfer enzyme of the nonoxidative pentose phosphate pathway.

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. Recombinant human TKT retained ThDP and Ca2+ strongly under cofactor-removal conditions used in the study.

    Human transketolase → Thiamine diphosphate source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure.
    experimental_model
    Recombinant human TKT crystallography, kinetics and NMR.
    limitations
    Retention is preparation- and protocol-specific; this is not a measurement of in vivo Mg depletion.
    nutrient_topic
    Magnesium research collection; topical membership is not evidence of a direct dietary effect. · Magnesium
    organism
    Homo sapiens
    plain_language
    The enzyme can retain loaded cofactors; free-metal changes need not immediately strip them away.
    primary_references
    [mitschke-2010-tkt] The Crystal Structure of Human Transketolase and New Insights into Its Mode of Action (2010). https://pmc.ncbi.nlm.nih.gov/articles/PMC2951230/ DOI: 10.1074/jbc.M110.149955
    tissue_or_cell_type
    Purified recombinant TKT

    Magnesium: cross-nutrient mechanisms and deficiency (2026-09-17) · lines 601–611

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human TKT crystallography, kinetics and NMR. · source_derived_draft · unverified_draft

    ### mg-tkt-tight-cofactor-retention Recombinant human TKT retained ThDP and Ca2+ strongly under cofactor-removal conditions used in the study. Condition category: normal nutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect. plain_language: The enzyme can retain loaded cofactors; free-metal changes need not immediately strip them away. organism: Homo sapiens tissue_or_cell_type: Purified recombinant TKT experimental_model: Recombinant human TKT crystallography, kinetics and NMR. limitations: Retention is preparation- and protocol-specific; this is not a measurement of in vivo Mg depletion. cross_nutrient: Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure. [mitschke-2010-tkt] The Crystal Structure of Human Transketolase and New Insights into Its Mode of Action (2010). https://pmc.ncbi.nlm.nih.gov/articles/PMC2951230/ DOI: 10.1074/jbc.M110.149955
    Complete structured claim and evidence

  2. Acid-quench NMR of human TKT identified the protonated form of the DHE-ThDP intermediate generated during the donor half-reaction.

    Human transketolase → 1,2-Dihydroxyethyl-ThDP intermediate source_derived_draftungraded
    Experimental context and source evidence
    evidence
    [{"paper_key": "mitschke-2010-tkt", "source_bundle": "artifacts/thiamine_metabolism_sources.json", "passage_ids": ["p-31", "p-44", "p-46", "p-47"], "locator": "acid quench", "preservation": "Exact text retained in the source bundle; full source document retained when openly retrievable."}]
    experimental_model
    Human recombinant TKT; chemical quench and NMR.
    limitations
    Acid quench protonates the intermediate; native enamine occupancy is inferred from trapped species.
    nutrient
    Thiamine (vitamin B1) · Thiamine (vitamin B1)
    nutrient_topic
    Thiamine research collection; topical membership is not evidence of a direct dietary effect. · Thiamine (vitamin B1)
    organism
    Homo sapiens
    plain_language
    B1 temporarily carries the two-carbon sugar fragment before its transfer to an acceptor; the detected acid-trapped form is distinguished from the reactive enamine.
    primary_references
    [mitschke-2010-tkt] The crystal structure of human transketolase and new insights into its mode of action (2010). https://pubmed.ncbi.nlm.nih.gov/20667822/ DOI: 10.1074/jbc.m110.149955
    tissue_or_cell_type
    Purified enzyme

    Thiamine: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 963–974

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human recombinant TKT; chemical quench and NMR. · source_derived_draft · unverified_draft

    ### b1-tkt-dhe-thdp-intermediate Acid-quench NMR of human TKT identified the protonated form of the DHE-ThDP intermediate generated during the donor half-reaction. Condition category: normal nutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect. plain_language: B1 temporarily carries the two-carbon sugar fragment before its transfer to an acceptor; the detected acid-trapped form is distinguished from the reactive enamine. organism: Homo sapiens tissue_or_cell_type: Purified enzyme experimental_model: Human recombinant TKT; chemical quench and NMR. limitations: Acid quench protonates the intermediate; native enamine occupancy is inferred from trapped species. evidence: [{"paper_key": "mitschke-2010-tkt", "source_bundle": "artifacts/thiamine_metabolism_sources.json", "passage_ids": ["p-31", "p-44", "p-46", "p-47"], "locator": "acid quench", "preservation": "Exact text retained in the source bundle; full source document retained when openly retrievable."}] nutrient: Thiamine (vitamin B1) [mitschke-2010-tkt] The crystal structure of human transketolase and new insights into its mode of action (2010). https://pubmed.ncbi.nlm.nih.gov/20667822/ DOI: 10.1074/jbc.m110.149955
    Complete structured claim and evidence

  3. Human TKT transfers two carbons from xylulose-5-phosphate to ribose-5-phosphate, yielding glyceraldehyde-3-phosphate and sedoheptulose-7-phosphate.

    Human transketolase → Nonoxidative pentose phosphate pathway source_derived_draftungraded
    Experimental context and source evidence
    evidence
    [{"paper_key": "mitschke-2010-tkt", "source_bundle": "artifacts/thiamine_metabolism_sources.json", "passage_ids": ["p-12"], "locator": "simplified reaction scheme", "preservation": "Exact text retained in the source bundle; full source document retained when openly retrievable."}]
    experimental_model
    Recombinant human TKT reaction analysis.
    limitations
    Direct reaction chemistry; indirect recycling effects on oxidative PPP flux need separate evidence.
    nutrient
    Thiamine (vitamin B1) · Thiamine (vitamin B1)
    nutrient_topic
    Thiamine research collection; topical membership is not evidence of a direct dietary effect. · Thiamine (vitamin B1)
    organism
    Homo sapiens
    plain_language
    B1 supports sugar rearrangement, connecting pentose and glycolytic intermediates. This reaction does not directly make NADPH.
    primary_references
    [mitschke-2010-tkt] The crystal structure of human transketolase and new insights into its mode of action (2010). https://pubmed.ncbi.nlm.nih.gov/20667822/ DOI: 10.1074/jbc.m110.149955
    tissue_or_cell_type
    Purified enzyme

    Thiamine: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 950–961

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human TKT reaction analysis. · source_derived_draft · unverified_draft

    ### b1-tkt-nonoxidative-carbon-transfer Human TKT transfers two carbons from xylulose-5-phosphate to ribose-5-phosphate, yielding glyceraldehyde-3-phosphate and sedoheptulose-7-phosphate. Condition category: normal nutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect. plain_language: B1 supports sugar rearrangement, connecting pentose and glycolytic intermediates. This reaction does not directly make NADPH. organism: Homo sapiens tissue_or_cell_type: Purified enzyme experimental_model: Recombinant human TKT reaction analysis. limitations: Direct reaction chemistry; indirect recycling effects on oxidative PPP flux need separate evidence. evidence: [{"paper_key": "mitschke-2010-tkt", "source_bundle": "artifacts/thiamine_metabolism_sources.json", "passage_ids": ["p-12"], "locator": "simplified reaction scheme", "preservation": "Exact text retained in the source bundle; full source document retained when openly retrievable."}] nutrient: Thiamine (vitamin B1) [mitschke-2010-tkt] The crystal structure of human transketolase and new insights into its mode of action (2010). https://pubmed.ncbi.nlm.nih.gov/20667822/ DOI: 10.1074/jbc.m110.149955
    Complete structured claim and evidence

What acts on it

  1. Native transketolase purified from human erythrocytes contained magnesium.

    Mg2+ → Human transketolase source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure.
    experimental_model
    Human erythrocyte transketolase; sulfur-35 ThDP binding and divalent-ion reconstitution.
    limitations
    Metal content in one preparation does not establish exclusive metal specificity.
    nutrient_topic
    Magnesium research collection; topical membership is not evidence of a direct dietary effect. · Magnesium
    organism
    Homo sapiens
    plain_language
    The isolated red-cell enzyme carried magnesium.
    primary_references
    [jung-1988-tkt] Studies on the nature of thiamine pyrophosphate binding and dependency on divalent cations of transketolase from human erythrocytes (1988). https://pubmed.ncbi.nlm.nih.gov/3248678/ DOI: 10.1016/0020-711x(88)90228-5
    tissue_or_cell_type
    Erythrocyte enzyme

    Magnesium: cross-nutrient mechanisms and deficiency (2026-09-17) · lines 553–563

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human erythrocyte transketolase; sulfur-35 ThDP binding and divalent-ion reconstitution. · source_derived_draft · unverified_draft

    ### mg-tkt-native-metal Native transketolase purified from human erythrocytes contained magnesium. Condition category: normal nutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect. plain_language: The isolated red-cell enzyme carried magnesium. organism: Homo sapiens tissue_or_cell_type: Erythrocyte enzyme experimental_model: Human erythrocyte transketolase; sulfur-35 ThDP binding and divalent-ion reconstitution. limitations: Metal content in one preparation does not establish exclusive metal specificity. cross_nutrient: Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure. [jung-1988-tkt] Studies on the nature of thiamine pyrophosphate binding and dependency on divalent cations of transketolase from human erythrocytes (1988). https://pubmed.ncbi.nlm.nih.gov/3248678/ DOI: 10.1016/0020-711x(88)90228-5
    Complete structured claim and evidence

  2. Reconstituted erythrocyte transketolase activity ranked Co2+ < Mn2+ < Ca2+ < Mg2+ in the tested assay.

    Calcium ion → Human transketolase source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure.
    experimental_model
    Human erythrocyte transketolase; sulfur-35 ThDP binding and divalent-ion reconstitution.
    limitations
    Replacement in vitro does not establish physiological substitution during Mg deficiency.
    nutrient_topic
    Magnesium research collection; topical membership is not evidence of a direct dietary effect. · Magnesium
    organism
    Homo sapiens
    plain_language
    Several divalent metals supported this B1-dependent enzyme; magnesium worked best here.
    primary_references
    [jung-1988-tkt] Studies on the nature of thiamine pyrophosphate binding and dependency on divalent cations of transketolase from human erythrocytes (1988). https://pubmed.ncbi.nlm.nih.gov/3248678/ DOI: 10.1016/0020-711x(88)90228-5
    tissue_or_cell_type
    Erythrocyte enzyme

    Magnesium: cross-nutrient mechanisms and deficiency (2026-09-17) · lines 565–575

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human erythrocyte transketolase; sulfur-35 ThDP binding and divalent-ion reconstitution. · source_derived_draft · unverified_draft

    ### mg-tkt-other-divalent-cations Reconstituted erythrocyte transketolase activity ranked Co2+ < Mn2+ < Ca2+ < Mg2+ in the tested assay. Condition category: normal nutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Several divalent metals supported this B1-dependent enzyme; magnesium worked best here. organism: Homo sapiens tissue_or_cell_type: Erythrocyte enzyme experimental_model: Human erythrocyte transketolase; sulfur-35 ThDP binding and divalent-ion reconstitution. limitations: Replacement in vitro does not establish physiological substitution during Mg deficiency. cross_nutrient: Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure. [jung-1988-tkt] Studies on the nature of thiamine pyrophosphate binding and dependency on divalent cations of transketolase from human erythrocytes (1988). https://pubmed.ncbi.nlm.nih.gov/3248678/ DOI: 10.1016/0020-711x(88)90228-5
    Complete structured claim and evidence

  3. Sulfur-35-labeled ThDP binding was measured directly in human erythrocyte transketolase.

    Thiamine diphosphate → Human transketolase source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure.
    experimental_model
    Human erythrocyte transketolase; sulfur-35 ThDP binding and divalent-ion reconstitution.
    limitations
    Binding measurement alone does not establish tissue flux.
    nutrient_topic
    Magnesium research collection; topical membership is not evidence of a direct dietary effect. · Magnesium
    organism
    Homo sapiens
    plain_language
    Tracer binding measures the vitamin-derived cofactor joining the enzyme.
    primary_references
    [jung-1988-tkt] Studies on the nature of thiamine pyrophosphate binding and dependency on divalent cations of transketolase from human erythrocytes (1988). https://pubmed.ncbi.nlm.nih.gov/3248678/ DOI: 10.1016/0020-711x(88)90228-5
    tissue_or_cell_type
    Erythrocyte enzyme

    Magnesium: cross-nutrient mechanisms and deficiency (2026-09-17) · lines 541–551

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human erythrocyte transketolase; sulfur-35 ThDP binding and divalent-ion reconstitution. · source_derived_draft · unverified_draft

    ### mg-tkt-radiolabeled-thdp-binding Sulfur-35-labeled ThDP binding was measured directly in human erythrocyte transketolase. Condition category: normal nutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Tracer binding measures the vitamin-derived cofactor joining the enzyme. organism: Homo sapiens tissue_or_cell_type: Erythrocyte enzyme experimental_model: Human erythrocyte transketolase; sulfur-35 ThDP binding and divalent-ion reconstitution. limitations: Binding measurement alone does not establish tissue flux. cross_nutrient: Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure. [jung-1988-tkt] Studies on the nature of thiamine pyrophosphate binding and dependency on divalent cations of transketolase from human erythrocytes (1988). https://pubmed.ncbi.nlm.nih.gov/3248678/ DOI: 10.1016/0020-711x(88)90228-5
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. In the 1974 report, blood transketolase recovered more slowly after thiamine in the hypomagnesemic patient than in two normomagnesemic patients.

    Mg2+ → Blood transketolase activity source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure.
    experimental_model
    Three acute Wernicke-Korsakoff patients: two normomagnesemic and one hypomagnesemic; serial blood transketolase and clinical assessment.
    limitations
    Three patients; blood transketolase is not direct brain flux.
    nutrient_topic
    Magnesium research collection; topical membership is not evidence of a direct dietary effect. · Magnesium
    organism
    Homo sapiens
    plain_language
    Low serum magnesium accompanied a delayed blood-enzyme response to B1.
    primary_references
    [traviesa-1974-thiamine] Magnesium deficiency: a possible cause of thiamine refractoriness in Wernicke-Korsakoff encephalopathy (1974). https://pubmed.ncbi.nlm.nih.gov/4420329/ DOI: 10.1136/jnnp.37.8.959
    tissue_or_cell_type
    Blood; acute Wernicke-Korsakoff patients
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Magnesium: cross-nutrient mechanisms and deficiency (2026-09-17) · lines 735–745

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Three acute Wernicke-Korsakoff patients: two normomagnesemic and one hypomagnesemic; serial blood transketolase and clinical assessment. · source_derived_draft · unverified_draft

    ### mg-thiamine-delayed-blood-tkt In the 1974 report, blood transketolase recovered more slowly after thiamine in the hypomagnesemic patient than in two normomagnesemic patients. Condition category: nutrient_deficiency nutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Low serum magnesium accompanied a delayed blood-enzyme response to B1. organism: Homo sapiens tissue_or_cell_type: Blood; acute Wernicke-Korsakoff patients experimental_model: Three acute Wernicke-Korsakoff patients: two normomagnesemic and one hypomagnesemic; serial blood transketolase and clinical assessment. limitations: Three patients; blood transketolase is not direct brain flux. cross_nutrient: Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure. [traviesa-1974-thiamine] Magnesium deficiency: a possible cause of thiamine refractoriness in Wernicke-Korsakoff encephalopathy (1974). https://pubmed.ncbi.nlm.nih.gov/4420329/ DOI: 10.1136/jnnp.37.8.959
    Complete structured claim and evidence

  2. In recombinant human TKT, Ca2+ coordinates the ThDP diphosphate and protein ligands at the active site.

    Calcium ion → Thiamine diphosphate source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure.
    experimental_model
    Recombinant human TKT crystallography, kinetics and NMR.
    limitations
    Ca-supported structural preparation does not quantify native human tissue metal occupancy.
    nutrient_topic
    Magnesium research collection; topical membership is not evidence of a direct dietary effect. · Magnesium
    organism
    Homo sapiens
    plain_language
    Calcium can anchor the B1-derived cofactor in active human transketolase.
    primary_references
    [mitschke-2010-tkt] The Crystal Structure of Human Transketolase and New Insights into Its Mode of Action (2010). https://pmc.ncbi.nlm.nih.gov/articles/PMC2951230/ DOI: 10.1074/jbc.M110.149955
    tissue_or_cell_type
    Recombinant TKT crystals

    Magnesium: cross-nutrient mechanisms and deficiency (2026-09-17) · lines 589–599

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human TKT crystallography, kinetics and NMR. · source_derived_draft · unverified_draft

    ### mg-tkt-calcium-thdp-anchor In recombinant human TKT, Ca2+ coordinates the ThDP diphosphate and protein ligands at the active site. Condition category: normal nutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Calcium can anchor the B1-derived cofactor in active human transketolase. organism: Homo sapiens tissue_or_cell_type: Recombinant TKT crystals experimental_model: Recombinant human TKT crystallography, kinetics and NMR. limitations: Ca-supported structural preparation does not quantify native human tissue metal occupancy. cross_nutrient: Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure. [mitschke-2010-tkt] The Crystal Structure of Human Transketolase and New Insights into Its Mode of Action (2010). https://pmc.ncbi.nlm.nih.gov/articles/PMC2951230/ DOI: 10.1074/jbc.M110.149955
    Complete structured claim and evidence

  3. Human erythrocyte apo-transketolase activation kinetics supported slow Mg-ThDP binding followed by slow isomerization.

    Magnesium-thiamine diphosphate complex → Transketolase cofactor loading source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure.
    experimental_model
    Human erythrocyte apo-transketolase reconstitution kinetics.
    limitations
    This is a kinetic interpretation; it differs from yeast reconstitution involving rate-limiting dimerization.
    nutrient_topic
    Magnesium research collection; topical membership is not evidence of a direct dietary effect. · Magnesium
    organism
    Homo sapiens
    plain_language
    The cofactor-loading complex contains ThDP and magnesium, not ATP.
    primary_references
    [booth-1993-tkt] Reconstitution of holotransketolase is by a thiamin-diphosphate-magnesium complex (1993). https://pubmed.ncbi.nlm.nih.gov/8243472/ DOI: 10.1111/j.1432-1033.1993.tb18373.x
    tissue_or_cell_type
    Erythrocyte apoenzyme

    Magnesium: cross-nutrient mechanisms and deficiency (2026-09-17) · lines 577–587

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human erythrocyte apo-transketolase reconstitution kinetics. · source_derived_draft · unverified_draft

    ### mg-tkt-loading-lag Human erythrocyte apo-transketolase activation kinetics supported slow Mg-ThDP binding followed by slow isomerization. Condition category: normal nutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect. plain_language: The cofactor-loading complex contains ThDP and magnesium, not ATP. organism: Homo sapiens tissue_or_cell_type: Erythrocyte apoenzyme experimental_model: Human erythrocyte apo-transketolase reconstitution kinetics. limitations: This is a kinetic interpretation; it differs from yeast reconstitution involving rate-limiting dimerization. cross_nutrient: Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure. [booth-1993-tkt] Reconstitution of holotransketolase is by a thiamin-diphosphate-magnesium complex (1993). https://pubmed.ncbi.nlm.nih.gov/8243472/ DOI: 10.1111/j.1432-1033.1993.tb18373.x
    Complete structured claim and evidence

  4. The trial found no significant between-group effect on its primary endpoint of change in erythrocyte transketolase activity.

    Magnesium sulfate → Blood transketolase activity source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    115 analyzed; biochemical measurement two hours after treatment.
    exposure
    Thiamine 250 mg as Pabrinex, magnesium sulfate 2 g, or both; biochemical samples at two hours. Initial magnesium-only group then received thiamine. Study regimens, not recommendations.
    limitations
    Does not refute molecular Mg requirements or prove no effect in deficient tissues; almost all participants lacked low erythrocyte ThDP.
    nutrient_topic
    Thiamine research collection; topical membership is not evidence of a direct dietary effect. · Thiamine (vitamin B1)
    organism
    Homo sapiens
    plain_language
    The enzyme endpoint did not improve significantly across treatment groups.
    primary_references
    [b1-maguire2022] Randomised trial of intravenous thiamine and/or magnesium sulphate administration on erythrocyte transketolase activity, lactate concentrations and alcohol withdrawal scores (2022). https://pubmed.ncbi.nlm.nih.gov/35484175/ DOI: 10.1038/s41598-022-10970-x
    tissue_or_cell_type
    Erythrocytes

    Thiamine: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1599–1609

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · 115 analyzed; biochemical measurement two hours after treatment. · source_derived_draft · unverified_draft

    ### b1-aws-mg-transketolase-null The trial found no significant between-group effect on its primary endpoint of change in erythrocyte transketolase activity. Condition category: normal nutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The enzyme endpoint did not improve significantly across treatment groups. organism: Homo sapiens tissue_or_cell_type: Erythrocytes experimental_model: 115 analyzed; biochemical measurement two hours after treatment. limitations: Does not refute molecular Mg requirements or prove no effect in deficient tissues; almost all participants lacked low erythrocyte ThDP. exposure: Thiamine 250 mg as Pabrinex, magnesium sulfate 2 g, or both; biochemical samples at two hours. Initial magnesium-only group then received thiamine. Study regimens, not recommendations. [b1-maguire2022] Randomised trial of intravenous thiamine and/or magnesium sulphate administration on erythrocyte transketolase activity, lactate concentrations and alcohol withdrawal scores (2022). https://pubmed.ncbi.nlm.nih.gov/35484175/ DOI: 10.1038/s41598-022-10970-x
    Complete structured claim and evidence

  5. Infant ETK activation coefficient differed significantly only between the highest maternal-dose group and placebo, whereas infant ThDP differed for all active groups.

    Thiamine (vitamin B1) → Erythrocyte transketolase activation coefficient source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    experimental_model
    Same infant biomarker comparison.
    exposure
    Maternal 0, 1.2, 2.4 or 10 mg/day thiamine from weeks 2-24 postpartum; study exposures only.
    limitations
    Assay response is not a contradiction: endpoints differ. The study did not establish a universal clinical threshold.
    nutrient_topic
    Thiamine research collection; topical membership is not evidence of a direct dietary effect. · Thiamine (vitamin B1)
    organism
    Homo sapiens
    plain_language
    The concentration marker and functional assay did not identify identical dose responses.
    primary_references
    [b1-gallant2021] Low-dose thiamine supplementation of lactating Cambodian mothers improves human milk thiamine concentrations: a randomized controlled trial (2021). https://pubmed.ncbi.nlm.nih.gov/33829271/ DOI: 10.1093/ajcn/nqab052
    tissue_or_cell_type
    Infant blood
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Thiamine: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1831–1841

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Same infant biomarker comparison. · source_derived_draft · unverified_draft

    ### b1-milk-trial-marker-difference Infant ETK activation coefficient differed significantly only between the highest maternal-dose group and placebo, whereas infant ThDP differed for all active groups. Condition category: biomarker_context nutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The concentration marker and functional assay did not identify identical dose responses. organism: Homo sapiens tissue_or_cell_type: Infant blood experimental_model: Same infant biomarker comparison. limitations: Assay response is not a contradiction: endpoints differ. The study did not establish a universal clinical threshold. exposure: Maternal 0, 1.2, 2.4 or 10 mg/day thiamine from weeks 2-24 postpartum; study exposures only. [b1-gallant2021] Low-dose thiamine supplementation of lactating Cambodian mothers improves human milk thiamine concentrations: a randomized controlled trial (2021). https://pubmed.ncbi.nlm.nih.gov/33829271/ DOI: 10.1093/ajcn/nqab052
    Complete structured claim and evidence

  6. Some at-risk patients had low erythrocyte ThDP with a normal activation test, and one had an abnormal activation test with normal ThDP.

    Erythrocyte thiamine diphosphate concentration → Erythrocyte transketolase activation coefficient source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    evidence_location
    Abstract Results; classification comparison
    evidence_span
    normal by the activation test but had low TDP
    experimental_model
    Human method-comparison study: HPLC erythrocyte/whole-blood ThDP, healthy reference cohorts and 63 patients considered at risk of deficiency compared with a transketolase activation test.
    exposure
    Laboratory assessment of thiamine status using erythrocytes or whole blood
    limitations
    Neither assay was independently validated against brain ThDP; no pooled sensitivity or specificity is inferred. The abstract contains inconsistent category totals, so no concordance percentage is calculated.
    nutrient_topic
    Thiamine research collection; topical membership is not evidence of a direct dietary effect. · Thiamine (vitamin B1)
    organism
    Homo sapiens
    plain_language
    The direct and functional tests sometimes classified the same patient differently.
    primary_references
    [talwar-2000-blood-thdp] Vitamin B(1) status assessed by direct measurement of thiamin pyrophosphate in erythrocytes or whole blood by HPLC: comparison with erythrocyte transketolase activation assay (2000). https://pubmed.ncbi.nlm.nih.gov/10794754/ DOI: 10.1093/clinchem/46.5.704
    tissue_or_cell_type
    Blood
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Thiamine: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1423–1435

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human method-comparison study: HPLC erythrocyte/whole-blood ThDP, healthy reference cohorts and 63 patients considered at risk of deficiency compared with a transketolase activation test. · source_derived_draft · unverified_draft

    ### thiamine-def-direct-functional-assay-discordance Some at-risk patients had low erythrocyte ThDP with a normal activation test, and one had an abnormal activation test with normal ThDP. Condition category: biomarker_context nutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The direct and functional tests sometimes classified the same patient differently. organism: Homo sapiens tissue_or_cell_type: Blood experimental_model: Human method-comparison study: HPLC erythrocyte/whole-blood ThDP, healthy reference cohorts and 63 patients considered at risk of deficiency compared with a transketolase activation test. limitations: Neither assay was independently validated against brain ThDP; no pooled sensitivity or specificity is inferred. The abstract contains inconsistent category totals, so no concordance percentage is calculated. evidence_location: Abstract Results; classification comparison evidence_span: normal by the activation test but had low TDP exposure: Laboratory assessment of thiamine status using erythrocytes or whole blood [talwar-2000-blood-thdp] Vitamin B(1) status assessed by direct measurement of thiamin pyrophosphate in erythrocytes or whole blood by HPLC: comparison with erythrocyte transketolase activation assay (2000). https://pubmed.ncbi.nlm.nih.gov/10794754/ DOI: 10.1093/clinchem/46.5.704
    Complete structured claim and evidence

  7. The functional erythrocyte test compared transketolase activity before and after adding exogenous thiamine diphosphate.

    Thiamine diphosphate → Blood transketolase activity source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    evidence_location
    Abstract
    evidence_span
    before and after activation with exogenous thiamin diphosphate
    experimental_model
    Human erythrocytes incubated with thiamine, plus alcoholic, elderly and student comparison groups; HPLC ThDP versus basal and ThDP-stimulated transketolase assays.
    exposure
    Laboratory assessment of thiamine status using erythrocytes or whole blood
    limitations
    Assay response is influenced by the enzyme preparation and assay conditions; a small response is not a measurement of every tissue.
    nutrient_topic
    Thiamine research collection; topical membership is not evidence of a direct dietary effect. · Thiamine (vitamin B1)
    organism
    Homo sapiens
    plain_language
    This asks how much extra cofactor can activate the sampled enzyme, whereas HPLC counts the cofactor itself.
    primary_references
    [baines-1988-erythrocyte-assays] The Evaluation of Erythrocyte Thiamin Diphosphate as an Indicator of Thiamin Status in Man, and its Comparison with Erythrocyte Transketolase Activity Measurements (1988). https://journals.sagepub.com/doi/10.1177/000456328802500617 DOI: 10.1177/000456328802500617
    tissue_or_cell_type
    Erythrocyte hemolysates
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Thiamine: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1381–1393

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human erythrocytes incubated with thiamine, plus alcoholic, elderly and student comparison groups; HPLC ThDP versus basal and ThDP-stimulated transketolase assays. · source_derived_draft · unverified_draft

    ### thiamine-def-exogenous-thdp-functional-assay The functional erythrocyte test compared transketolase activity before and after adding exogenous thiamine diphosphate. Condition category: biomarker_context nutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect. plain_language: This asks how much extra cofactor can activate the sampled enzyme, whereas HPLC counts the cofactor itself. organism: Homo sapiens tissue_or_cell_type: Erythrocyte hemolysates experimental_model: Human erythrocytes incubated with thiamine, plus alcoholic, elderly and student comparison groups; HPLC ThDP versus basal and ThDP-stimulated transketolase assays. limitations: Assay response is influenced by the enzyme preparation and assay conditions; a small response is not a measurement of every tissue. evidence_location: Abstract evidence_span: before and after activation with exogenous thiamin diphosphate exposure: Laboratory assessment of thiamine status using erythrocytes or whole blood [baines-1988-erythrocyte-assays] The Evaluation of Erythrocyte Thiamin Diphosphate as an Indicator of Thiamin Status in Man, and its Comparison with Erythrocyte Transketolase Activity Measurements (1988). https://journals.sagepub.com/doi/10.1177/000456328802500617 DOI: 10.1177/000456328802500617
    Complete structured claim and evidence

  8. Direct erythrocyte ThDP was more stable during frozen storage than transketolase activity in the evaluated preparations.

    Erythrocyte thiamine diphosphate concentration → Blood transketolase activity source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    evidence_location
    Abstract
    evidence_span
    ETDP is more stable than ETKA in frozen erythrocytes
    experimental_model
    Human erythrocytes incubated with thiamine, plus alcoholic, elderly and student comparison groups; HPLC ThDP versus basal and ThDP-stimulated transketolase assays.
    exposure
    Laboratory assessment of thiamine status using erythrocytes or whole blood
    limitations
    Historical assay comparison, not a validated stability duration for every modern collection tube or analytical platform.
    nutrient_topic
    Thiamine research collection; topical membership is not evidence of a direct dietary effect. · Thiamine (vitamin B1)
    organism
    Homo sapiens
    plain_language
    Storage can affect the chemical measurement and the functional enzyme test differently.
    primary_references
    [baines-1988-erythrocyte-assays] The Evaluation of Erythrocyte Thiamin Diphosphate as an Indicator of Thiamin Status in Man, and its Comparison with Erythrocyte Transketolase Activity Measurements (1988). https://journals.sagepub.com/doi/10.1177/000456328802500617 DOI: 10.1177/000456328802500617
    tissue_or_cell_type
    Frozen erythrocyte specimens
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Thiamine: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1395–1407

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human erythrocytes incubated with thiamine, plus alcoholic, elderly and student comparison groups; HPLC ThDP versus basal and ThDP-stimulated transketolase assays. · source_derived_draft · unverified_draft

    ### thiamine-def-frozen-erythrocyte-stability Direct erythrocyte ThDP was more stable during frozen storage than transketolase activity in the evaluated preparations. Condition category: biomarker_context nutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Storage can affect the chemical measurement and the functional enzyme test differently. organism: Homo sapiens tissue_or_cell_type: Frozen erythrocyte specimens experimental_model: Human erythrocytes incubated with thiamine, plus alcoholic, elderly and student comparison groups; HPLC ThDP versus basal and ThDP-stimulated transketolase assays. limitations: Historical assay comparison, not a validated stability duration for every modern collection tube or analytical platform. evidence_location: Abstract evidence_span: ETDP is more stable than ETKA in frozen erythrocytes exposure: Laboratory assessment of thiamine status using erythrocytes or whole blood [baines-1988-erythrocyte-assays] The Evaluation of Erythrocyte Thiamin Diphosphate as an Indicator of Thiamin Status in Man, and its Comparison with Erythrocyte Transketolase Activity Measurements (1988). https://journals.sagepub.com/doi/10.1177/000456328802500617 DOI: 10.1177/000456328802500617
    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