Component

Alpha-ketobutyrate

Context-specific entity; species, compartment and exposure are stated on each claim.

6 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What it acts on

  1. 2-Oxobutyrate inhibited BCOADC kinase, and reduced BCOADC phosphorylation was observed in isolated adipocytes.

    Alpha-ketobutyrate → BCOADC kinase in the 1986 study, source species unverified source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Purified kinase and isolated-adipocyte assays; species unverified from abstract.
    limitations
    This does not prove that a threonine supplement changes BCAA oxidation in humans. Correction record: PubMed indexes an erratum in Biochemical Journal 1987;242(3):935. The notice text was inaccessible during this curation; its specific scope and impact remain unverified. The purified-enzyme findings are retained provisionally with this flag, and the abstract does not identify the source species. https://pubmed.ncbi.nlm.nih.gov/3800905/
    nutrient_topic
    L-Threonine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Threonine
    plain_language
    A catabolic intermediate can influence the regulatory brake on its disposal machinery.
    primary_references
    Oxidative decarboxylation of 4-methylthio-2-oxobutyrate by branched-chain 2-oxo acid dehydrogenase complex. · 1986 · https://pubmed.ncbi.nlm.nih.gov/3800905/ · DOI 10.1042/bj2370621

    L-Threonine: translation, intestinal barrier, metabolism and cross-nutrient mechanisms (2026-09-19) · lines 314–320

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Purified kinase and isolated-adipocyte assays; species unverified from abstract. · source_derived_draft · unverified_draft

    ## l-threonine-ketoacid-feedback A catabolic intermediate can influence the regulatory brake on its disposal machinery. 2-Oxobutyrate inhibited BCOADC kinase, and reduced BCOADC phosphorylation was observed in isolated adipocytes. Model: Purified kinase and isolated-adipocyte assays; species unverified from abstract. Limitations: This does not prove that a threonine supplement changes BCAA oxidation in humans. Correction record: PubMed indexes an erratum in Biochemical Journal 1987;242(3):935. The notice text was inaccessible during this curation; its specific scope and impact remain unverified. The purified-enzyme findings are retained provisionally with this flag, and the abstract does not identify the source species. https://pubmed.ncbi.nlm.nih.gov/3800905/ Evidence access: Primary abstract Oxidative decarboxylation of 4-methylthio-2-oxobutyrate by branched-chain 2-oxo acid dehydrogenase complex. · 1986 · https://pubmed.ncbi.nlm.nih.gov/3800905/ · DOI 10.1042/bj2370621
    Complete structured claim and evidence

What acts on it

  1. Purified human hepatic serine dehydratase showed L-threonine dehydratase activity in comparison with the human SDH-like isoform.

    Human hepatic serine dehydratase / SDS → Alpha-ketobutyrate source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Human recombinant enzymes expressed in E. coli and compared biochemically.
    limitations
    Activity in a purified system does not quantify whole-body human threonine flux. The threonine product is alpha-ketobutyrate, distinct from the serine product pyruvate.
    nutrient_topic
    L-Threonine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Threonine
    plain_language
    Threonine can enter carbon metabolism through an enzyme it shares with serine.
    primary_references
    Enzymatic and biochemical properties of a novel human serine dehydratase isoform. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16580895/ · DOI 10.1016/j.bbapap.2006.02.010

    L-Threonine: translation, intestinal barrier, metabolism and cross-nutrient mechanisms (2026-09-19) · lines 250–256

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human recombinant enzymes expressed in E. coli and compared biochemically. · source_derived_draft · unverified_draft

    ## l-threonine-human-sds-catabolism Threonine can enter carbon metabolism through an enzyme it shares with serine. Purified human hepatic serine dehydratase showed L-threonine dehydratase activity in comparison with the human SDH-like isoform. Model: Human recombinant enzymes expressed in E. coli and compared biochemically. Limitations: Activity in a purified system does not quantify whole-body human threonine flux. The threonine product is alpha-ketobutyrate, distinct from the serine product pyruvate. Evidence access: Primary abstract Enzymatic and biochemical properties of a novel human serine dehydratase isoform. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16580895/ · DOI 10.1016/j.bbapap.2006.02.010
    Complete structured claim and evidence

  2. The recombinant human SDH-like protein also had threonine dehydratase activity, with kinetic constants differing substantially from hepatic SDS.

    Human serine dehydratase-like protein / SDSL → Alpha-ketobutyrate source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Comparative human enzyme kinetics and PLP-binding measurements.
    limitations
    Isoform abundance in cultured cells was low; catalytic capacity does not establish its dominant tissue role.
    nutrient_topic
    L-Threonine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Threonine
    plain_language
    Closely related enzymes can process the same substrate at different rates.
    primary_references
    Enzymatic and biochemical properties of a novel human serine dehydratase isoform. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16580895/ · DOI 10.1016/j.bbapap.2006.02.010

    L-Threonine: translation, intestinal barrier, metabolism and cross-nutrient mechanisms (2026-09-19) · lines 258–264

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Comparative human enzyme kinetics and PLP-binding measurements. · source_derived_draft · unverified_draft

    ## l-threonine-human-sdsl-catabolism Closely related enzymes can process the same substrate at different rates. The recombinant human SDH-like protein also had threonine dehydratase activity, with kinetic constants differing substantially from hepatic SDS. Model: Comparative human enzyme kinetics and PLP-binding measurements. Limitations: Isoform abundance in cultured cells was low; catalytic capacity does not establish its dominant tissue role. Evidence access: Primary abstract Enzymatic and biochemical properties of a novel human serine dehydratase isoform. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16580895/ · DOI 10.1016/j.bbapap.2006.02.010
    Complete structured claim and evidence

  3. Purified BCOADC oxidized 2-oxobutyrate with a reported Km of 18 micromolar; purified PDC also accepted it, whereas OGDH did not.

    Purified BCOADC in the 1986 ketoacid study, source species unverified → Alpha-ketobutyrate source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Purified-enzyme comparison; source species is not specified in the accessible abstract.
    limitations
    This is not recorded as direct human enzyme evidence or an exclusive BCKDH route. Correction record: PubMed indexes an erratum in Biochemical Journal 1987;242(3):935. The notice text was inaccessible during this curation; its specific scope and impact remain unverified. The purified-enzyme findings are retained provisionally with this flag, and the abstract does not identify the source species. https://pubmed.ncbi.nlm.nih.gov/3800905/
    nutrient_topic
    L-Threonine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Threonine
    plain_language
    More than one ketoacid complex can handle this carbon skeleton in vitro.
    primary_references
    Oxidative decarboxylation of 4-methylthio-2-oxobutyrate by branched-chain 2-oxo acid dehydrogenase complex. · 1986 · https://pubmed.ncbi.nlm.nih.gov/3800905/ · DOI 10.1042/bj2370621

    L-Threonine: translation, intestinal barrier, metabolism and cross-nutrient mechanisms (2026-09-19) · lines 306–312

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Purified-enzyme comparison; source species is not specified in the accessible abstract. · source_derived_draft · unverified_draft

    ## l-threonine-ketoacid-oxidation More than one ketoacid complex can handle this carbon skeleton in vitro. Purified BCOADC oxidized 2-oxobutyrate with a reported Km of 18 micromolar; purified PDC also accepted it, whereas OGDH did not. Model: Purified-enzyme comparison; source species is not specified in the accessible abstract. Limitations: This is not recorded as direct human enzyme evidence or an exclusive BCKDH route. Correction record: PubMed indexes an erratum in Biochemical Journal 1987;242(3):935. The notice text was inaccessible during this curation; its specific scope and impact remain unverified. The purified-enzyme findings are retained provisionally with this flag, and the abstract does not identify the source species. https://pubmed.ncbi.nlm.nih.gov/3800905/ Evidence access: Primary abstract Oxidative decarboxylation of 4-methylthio-2-oxobutyrate by branched-chain 2-oxo acid dehydrogenase complex. · 1986 · https://pubmed.ncbi.nlm.nih.gov/3800905/ · DOI 10.1042/bj2370621
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Respiration-deficient proliferating cells became limited in aspartate synthesis; alpha-ketobutyrate restored proliferation as an electron acceptor without supplying carbon or ATP.

    Respiration-deficient proliferating cell models → L-Aspartate source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_access
    Primary full text
    experimental_model
    Cultured proliferating mammalian cells with impaired respiration.
    limitations
    ATP is not generally dispensable; this experiment isolates an electron-acceptor bottleneck in supplied culture conditions.
    nutrient_topic
    NAD+ collection; molecular form, preparation, species, exposure and manipulation remain explicit. · NAD+
    plain_language
    Respiration supports building material by restoring electron acceptors, as well as producing ATP.
    primary_references
    Supporting Aspartate Biosynthesis Is an Essential Function of Respiration in Proliferating Cells. · 2015 · https://pubmed.ncbi.nlm.nih.gov/26232225/ · DOI 10.1016/j.cell.2015.07.017
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    NAD+: compartmental supply, consumption and cross-nutrient mechanisms (2026-09-19) · lines 204–210

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Cultured proliferating mammalian cells with impaired respiration. · source_derived_draft · unverified_draft

    ## nad-plus-electron-acceptor-aspartate Respiration supports building material by restoring electron acceptors, as well as producing ATP. Respiration-deficient proliferating cells became limited in aspartate synthesis; alpha-ketobutyrate restored proliferation as an electron acceptor without supplying carbon or ATP. Model: Cultured proliferating mammalian cells with impaired respiration. Limitations: ATP is not generally dispensable; this experiment isolates an electron-acceptor bottleneck in supplied culture conditions. Evidence access: Primary full text Supporting Aspartate Biosynthesis Is an Essential Function of Respiration in Proliferating Cells. · 2015 · https://pubmed.ncbi.nlm.nih.gov/26232225/ · DOI 10.1016/j.cell.2015.07.017
    Complete structured claim and evidence

  2. E. coli mutant and enzyme studies showed TdcE conversion of threonine-derived 2-ketobutyrate into propionyl-CoA during anaerobic growth.

    Escherichia coli 2-ketobutyrate formate-lyase / TdcE → Propionyl-CoA source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    E. coli operon analysis, mutants, enzyme assays and culture-supernatant NMR.
    limitations
    This is not a human enzyme reaction or a measurement of net propionate production in the human gut.
    nutrient_topic
    L-Threonine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Threonine
    plain_language
    Microbes have a separate route for fermenting threonine carbon.
    primary_references
    Novel keto acid formate-lyase and propionate kinase enzymes are components of an anaerobic pathway in Escherichia coli that degrades L-threonine to propionate. · 1998 · https://pubmed.ncbi.nlm.nih.gov/9484901/ · DOI 10.1046/j.1365-2958.1998.00696.x

    L-Threonine: translation, intestinal barrier, metabolism and cross-nutrient mechanisms (2026-09-19) · lines 426–432

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · E. coli operon analysis, mutants, enzyme assays and culture-supernatant NMR. · source_derived_draft · unverified_draft

    ## l-threonine-microbial-ketoacid Microbes have a separate route for fermenting threonine carbon. E. coli mutant and enzyme studies showed TdcE conversion of threonine-derived 2-ketobutyrate into propionyl-CoA during anaerobic growth. Model: E. coli operon analysis, mutants, enzyme assays and culture-supernatant NMR. Limitations: This is not a human enzyme reaction or a measurement of net propionate production in the human gut. Evidence access: Primary abstract Novel keto acid formate-lyase and propionate kinase enzymes are components of an anaerobic pathway in Escherichia coli that degrades L-threonine to propionate. · 1998 · https://pubmed.ncbi.nlm.nih.gov/9484901/ · DOI 10.1046/j.1365-2958.1998.00696.x
    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.

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