Component

Human 3-methylcrotonyl-CoA carboxylase complex

Human 3-methylcrotonyl-CoA carboxylase complex. Species, exposure and limitations are retained in each linked claim.

8 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 MCC had an ATP Km of 45 ± 11 micromolar and a methylcrotonyl-CoA Km of 74 ± 7 micromolar.

    Human 3-methylcrotonyl-CoA carboxylase complex → ATP source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/biotin-research/17360195.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3ae046490d9657d005d5c39efb1f7439bc015d0cb2190834e3e868de70eaf985", "start_char": 0, "end_char": 1067, "text_sha256": "3ae046490d9657d005d5c39efb1f7439bc015d0cb2190834e3e868de70eaf985"}
    experimental_model
    Purified recombinant human MCC produced by baculovirus expression
    exposure
    ATP and methylcrotonyl-CoA kinetics
    limitations
    Recombinant-enzyme kinetics do not determine human dietary requirements.
    nutrient_topic
    Biotin research collection; topical membership is not evidence of a direct dietary effect. · Biotin
    organism
    Homo sapiens
    plain_language
    The biotin-dependent reaction also requires an energy substrate and the carbon substrate.
    primary_references
    [b7-p17360195] Expression, purification, characterization of human 3-methylcrotonyl-CoA carboxylase (MCCC). (2007). https://pubmed.ncbi.nlm.nih.gov/17360195/ DOI: 10.1016/j.pep.2007.01.012
    tissue_or_cell_type
    Purified human MCC complex

    Biotin: carboxylases, recycling, deficiency and nutrient interactions (2026-09-17) · lines 780–791

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified recombinant human MCC produced by baculovirus expression · source_derived_draft · unverified_draft

    ### b7-mcc-atp Recombinant human MCC had an ATP Km of 45 ± 11 micromolar and a methylcrotonyl-CoA Km of 74 ± 7 micromolar. Condition category: normal nutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect. plain_language: The biotin-dependent reaction also requires an energy substrate and the carbon substrate. organism: Homo sapiens tissue_or_cell_type: Purified human MCC complex experimental_model: Purified recombinant human MCC produced by baculovirus expression limitations: Recombinant-enzyme kinetics do not determine human dietary requirements. exposure: ATP and methylcrotonyl-CoA kinetics evidence_span: {"source_cache": "artifacts/biotin-research/17360195.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3ae046490d9657d005d5c39efb1f7439bc015d0cb2190834e3e868de70eaf985", "start_char": 0, "end_char": 1067, "text_sha256": "3ae046490d9657d005d5c39efb1f7439bc015d0cb2190834e3e868de70eaf985"} [b7-p17360195] Expression, purification, characterization of human 3-methylcrotonyl-CoA carboxylase (MCCC). (2007). https://pubmed.ncbi.nlm.nih.gov/17360195/ DOI: 10.1016/j.pep.2007.01.012
    Complete structured claim and evidence

  2. In the 88-person MCC-deficiency series, 57% were asymptomatic; 12 had acute metabolic decompensations, and genotype or biochemical phenotype did not reliably predict the course.

    Human 3-methylcrotonyl-CoA carboxylase complex → Clinical course of human isolated MCC deficiency source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/biotin-research/22642865.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "f0c40118afe81e9b597d2d2cbe6a785c2b96a4dbd7f4dcb634230070c61865ee", "start_char": 0, "end_char": 1384, "text_sha256": "f0c40118afe81e9b597d2d2cbe6a785c2b96a4dbd7f4dcb634230070c61865ee"}
    experimental_model
    Retrospective clinical, biochemical and molecular study of 88 MCC-deficient individuals
    exposure
    MCCC1/MCCC2 defects; mixed newborn screening and clinical ascertainment
    limitations
    Ascertainment bias and incomplete penetrance limit predictions. This is an isolated inherited enzyme defect, not biotin intake deficiency.
    nutrient_topic
    Biotin research collection; topical membership is not evidence of a direct dietary effect. · Biotin
    organism
    Homo sapiens
    plain_language
    A striking biochemical marker does not determine how ill a person will be.
    primary_references
    [b7-p22642865] 3-methylcrotonyl-CoA carboxylase deficiency: clinical, biochemical, enzymatic and molecular studies in 88 individuals. (2012). https://pubmed.ncbi.nlm.nih.gov/22642865/ DOI: 10.1186/1750-1172-7-31
    tissue_or_cell_type
    Clinical and biochemical phenotype
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Biotin: carboxylases, recycling, deficiency and nutrient interactions (2026-09-17) · lines 1027–1038

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Retrospective clinical, biochemical and molecular study of 88 MCC-deficient individuals · source_derived_draft · unverified_draft

    ### b7-mcc-genetic-variability In the 88-person MCC-deficiency series, 57% were asymptomatic; 12 had acute metabolic decompensations, and genotype or biochemical phenotype did not reliably predict the course. Condition category: machinery_impairment nutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect. plain_language: A striking biochemical marker does not determine how ill a person will be. organism: Homo sapiens tissue_or_cell_type: Clinical and biochemical phenotype experimental_model: Retrospective clinical, biochemical and molecular study of 88 MCC-deficient individuals limitations: Ascertainment bias and incomplete penetrance limit predictions. This is an isolated inherited enzyme defect, not biotin intake deficiency. exposure: MCCC1/MCCC2 defects; mixed newborn screening and clinical ascertainment evidence_span: {"source_cache": "artifacts/biotin-research/22642865.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "f0c40118afe81e9b597d2d2cbe6a785c2b96a4dbd7f4dcb634230070c61865ee", "start_char": 0, "end_char": 1384, "text_sha256": "f0c40118afe81e9b597d2d2cbe6a785c2b96a4dbd7f4dcb634230070c61865ee"} [b7-p22642865] 3-methylcrotonyl-CoA carboxylase deficiency: clinical, biochemical, enzymatic and molecular studies in 88 individuals. (2012). https://pubmed.ncbi.nlm.nih.gov/22642865/ DOI: 10.1186/1750-1172-7-31
    Complete structured claim and evidence

  3. MCC converts 3-methylcrotonyl-CoA to 3-methylglutaconyl-CoA in the leucine breakdown pathway using biotin.

    Human 3-methylcrotonyl-CoA carboxylase complex → 3-Methylcrotonyl-CoA source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/biotin-research/21918059.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "5cf1d7e25ae7bdfeb2ac3225cee8e4e660723d5197fc057f63327b3ad9eb3aaf", "start_char": 0, "end_char": 1723, "text_sha256": "5cf1d7e25ae7bdfeb2ac3225cee8e4e660723d5197fc057f63327b3ad9eb3aaf"}
    experimental_model
    Two human egg-white biotin-depletion cohorts with leucine challenges
    exposure
    28-day depletion in cohorts of 5 and 7 adults
    limitations
    Biomarker challenge study; the core MCC reaction is pathway background, not a new structural discovery.
    nutrient_topic
    Biotin research collection; topical membership is not evidence of a direct dietary effect. · Biotin
    organism
    Homo sapiens
    plain_language
    Biotin helps process a carbon intermediate produced while breaking down leucine.
    primary_references
    [b7-p21918059] Urinary excretion of 3-hydroxyisovaleric acid and 3-hydroxyisovaleryl carnitine increases in response to a leucine challenge in marginally biotin-deficient humans. (2011). https://pubmed.ncbi.nlm.nih.gov/21918059/ DOI: 10.3945/jn.111.146126
    tissue_or_cell_type
    Leucine metabolism and urine

    Biotin: carboxylases, recycling, deficiency and nutrient interactions (2026-09-17) · lines 793–804

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Two human egg-white biotin-depletion cohorts with leucine challenges · source_derived_draft · unverified_draft

    ### b7-mcc-reaction MCC converts 3-methylcrotonyl-CoA to 3-methylglutaconyl-CoA in the leucine breakdown pathway using biotin. Condition category: normal nutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Biotin helps process a carbon intermediate produced while breaking down leucine. organism: Homo sapiens tissue_or_cell_type: Leucine metabolism and urine experimental_model: Two human egg-white biotin-depletion cohorts with leucine challenges limitations: Biomarker challenge study; the core MCC reaction is pathway background, not a new structural discovery. exposure: 28-day depletion in cohorts of 5 and 7 adults evidence_span: {"source_cache": "artifacts/biotin-research/21918059.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "5cf1d7e25ae7bdfeb2ac3225cee8e4e660723d5197fc057f63327b3ad9eb3aaf", "start_char": 0, "end_char": 1723, "text_sha256": "5cf1d7e25ae7bdfeb2ac3225cee8e4e660723d5197fc057f63327b3ad9eb3aaf"} [b7-p21918059] Urinary excretion of 3-hydroxyisovaleric acid and 3-hydroxyisovaleryl carnitine increases in response to a leucine challenge in marginally biotin-deficient humans. (2011). https://pubmed.ncbi.nlm.nih.gov/21918059/ DOI: 10.3945/jn.111.146126
    Complete structured claim and evidence

What acts on it

  1. Structural comparisons supported substrate-dependent, coordinated activation of human MCC.

    3-Methylcrotonyl-CoA → Human 3-methylcrotonyl-CoA carboxylase complex source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/biotin-research/39223421.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "221115ee36b8452b3915e000ae5f363f8f771705dcbb17570343b8f536b7c87a", "start_char": 0, "end_char": 1050, "text_sha256": "221115ee36b8452b3915e000ae5f363f8f771705dcbb17570343b8f536b7c87a"}
    experimental_model
    Structures of purified endogenous human MCC, PCC and PC; substrate-bound MCC conformations
    exposure
    Cryo-EM and substrate-bound structural analysis
    limitations
    Indexed abstract and publisher preview inspected; detailed residue-level claims require full-paper review. Published online 2024, journal issue 2025.
    nutrient_topic
    Biotin research collection; topical membership is not evidence of a direct dietary effect. · Biotin
    organism
    Homo sapiens
    plain_language
    Adding substrate reorganizes the working enzyme; the word synergy here refers to enzyme parts, not proven synergy between supplements.
    primary_references
    [b7-p39223421] Structural insight into synergistic activation of human 3-methylcrotonyl-CoA carboxylase. (2025). https://pubmed.ncbi.nlm.nih.gov/39223421/ DOI: 10.1038/s41594-024-01379-3
    tissue_or_cell_type
    Purified endogenous mitochondrial carboxylases

    Biotin: carboxylases, recycling, deficiency and nutrient interactions (2026-09-17) · lines 806–817

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Structures of purified endogenous human MCC, PCC and PC; substrate-bound MCC conformations · source_derived_draft · unverified_draft

    ### b7-mcc-substrate-conformations Structural comparisons supported substrate-dependent, coordinated activation of human MCC. Condition category: normal nutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Adding substrate reorganizes the working enzyme; the word synergy here refers to enzyme parts, not proven synergy between supplements. organism: Homo sapiens tissue_or_cell_type: Purified endogenous mitochondrial carboxylases experimental_model: Structures of purified endogenous human MCC, PCC and PC; substrate-bound MCC conformations limitations: Indexed abstract and publisher preview inspected; detailed residue-level claims require full-paper review. Published online 2024, journal issue 2025. exposure: Cryo-EM and substrate-bound structural analysis evidence_span: {"source_cache": "artifacts/biotin-research/39223421.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "221115ee36b8452b3915e000ae5f363f8f771705dcbb17570343b8f536b7c87a", "start_char": 0, "end_char": 1050, "text_sha256": "221115ee36b8452b3915e000ae5f363f8f771705dcbb17570343b8f536b7c87a"} [b7-p39223421] Structural insight into synergistic activation of human 3-methylcrotonyl-CoA carboxylase. (2025). https://pubmed.ncbi.nlm.nih.gov/39223421/ DOI: 10.1038/s41594-024-01379-3
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Biotin-deficient but carnitine-sufficient HepG2 cells had more than tenfold higher intracellular 3-hydroxyisovalerylcarnitine than doubly sufficient cells.

    Biotin → HepG2 3-hydroxyisovalerylcarnitine pool source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/biotin-research/25527659.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4a368eb2fa2020bb1cabc99b31a3420870a8256886d5934d3d834c90b078238f", "start_char": 0, "end_char": 2372, "text_sha256": "4a368eb2fa2020bb1cabc99b31a3420870a8256886d5934d3d834c90b078238f"}
    experimental_model
    Two-factor biotin/carnitine depletion and carnitine repletion in human HepG2 cells
    exposure
    Separate and combined biotin and carnitine depletion
    limitations
    This is a cell-culture demonstration of marker masking; it does not validate a diagnostic correction formula in pregnancy or the general population.
    nutrient_topic
    Biotin research collection; topical membership is not evidence of a direct dietary effect. · Biotin
    organism
    Homo sapiens
    plain_language
    When carnitine is available, the biotin-related bottleneck produces a strong side-product signal.
    primary_references
    [b7-p25527659] In HepG2 cells, coexisting carnitine deficiency masks important indicators of marginal biotin deficiency. (2015). https://pubmed.ncbi.nlm.nih.gov/25527659/ DOI: 10.3945/jn.114.201343
    tissue_or_cell_type
    HepG2 hepatoma cells
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Biotin: carboxylases, recycling, deficiency and nutrient interactions (2026-09-17) · lines 949–960

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Two-factor biotin/carnitine depletion and carnitine repletion in human HepG2 cells · source_derived_draft · unverified_draft

    ### b7-c5oh-biotin-low Biotin-deficient but carnitine-sufficient HepG2 cells had more than tenfold higher intracellular 3-hydroxyisovalerylcarnitine than doubly sufficient cells. Condition category: nutrient_deficiency nutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect. plain_language: When carnitine is available, the biotin-related bottleneck produces a strong side-product signal. organism: Homo sapiens tissue_or_cell_type: HepG2 hepatoma cells experimental_model: Two-factor biotin/carnitine depletion and carnitine repletion in human HepG2 cells limitations: This is a cell-culture demonstration of marker masking; it does not validate a diagnostic correction formula in pregnancy or the general population. exposure: Separate and combined biotin and carnitine depletion evidence_span: {"source_cache": "artifacts/biotin-research/25527659.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4a368eb2fa2020bb1cabc99b31a3420870a8256886d5934d3d834c90b078238f", "start_char": 0, "end_char": 2372, "text_sha256": "4a368eb2fa2020bb1cabc99b31a3420870a8256886d5934d3d834c90b078238f"} [b7-p25527659] In HepG2 cells, coexisting carnitine deficiency masks important indicators of marginal biotin deficiency. (2015). https://pubmed.ncbi.nlm.nih.gov/25527659/ DOI: 10.3945/jn.114.201343
    Complete structured claim and evidence

  2. Urinary 3-HIA increased during 28-day biotin depletion in 11 adults; biotin-status indicators normalized in most after one week on a general diet.

    Biotin → Human urinary 3-hydroxyisovaleric acid excretion source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/biotin-research/12399279.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "38158dd10cfc6528b65a3304fac58a5b5d8ec82e20673534b5bf6e9e79f14b09", "start_char": 0, "end_char": 1718, "text_sha256": "38158dd10cfc6528b65a3304fac58a5b5d8ec82e20673534b5bf6e9e79f14b09"}
    experimental_model
    Experimental depletion/repletion in 11 healthy adults; leucine challenge in 5
    exposure
    28 days of egg-white diet followed by general diet with or without 80 micrograms supplemental biotin
    limitations
    An intentional undenatured egg-white diet is not ordinary cooked-egg intake. Small experimental cohorts do not establish a population-wide threshold.
    nutrient_topic
    Biotin research collection; topical membership is not evidence of a direct dietary effect. · Biotin
    organism
    Homo sapiens
    plain_language
    A bottleneck in leucine breakdown became measurable before a universal clinical syndrome was required.
    primary_references
    [b7-p12399279] Indicators of marginal biotin deficiency and repletion in humans: validation of 3-hydroxyisovaleric acid excretion and a leucine challenge. (2002). https://pubmed.ncbi.nlm.nih.gov/12399279/ DOI: 10.1093/ajcn/76.5.1061
    tissue_or_cell_type
    Dietary exposure and urinary metabolites
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Biotin: carboxylases, recycling, deficiency and nutrient interactions (2026-09-17) · lines 897–908

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Experimental depletion/repletion in 11 healthy adults; leucine challenge in 5 · source_derived_draft · unverified_draft

    ### b7-depletion-3hia Urinary 3-HIA increased during 28-day biotin depletion in 11 adults; biotin-status indicators normalized in most after one week on a general diet. Condition category: nutrient_deficiency nutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect. plain_language: A bottleneck in leucine breakdown became measurable before a universal clinical syndrome was required. organism: Homo sapiens tissue_or_cell_type: Dietary exposure and urinary metabolites experimental_model: Experimental depletion/repletion in 11 healthy adults; leucine challenge in 5 limitations: An intentional undenatured egg-white diet is not ordinary cooked-egg intake. Small experimental cohorts do not establish a population-wide threshold. exposure: 28 days of egg-white diet followed by general diet with or without 80 micrograms supplemental biotin evidence_span: {"source_cache": "artifacts/biotin-research/12399279.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "38158dd10cfc6528b65a3304fac58a5b5d8ec82e20673534b5bf6e9e79f14b09", "start_char": 0, "end_char": 1718, "text_sha256": "38158dd10cfc6528b65a3304fac58a5b5d8ec82e20673534b5bf6e9e79f14b09"} [b7-p12399279] Indicators of marginal biotin deficiency and repletion in humans: validation of 3-hydroxyisovaleric acid excretion and a leucine challenge. (2002). https://pubmed.ncbi.nlm.nih.gov/12399279/ DOI: 10.1093/ajcn/76.5.1061
    Complete structured claim and evidence

  3. Challenge-induced urinary 3-HIA rose more than twofold by day 14 in both biotin-depleted cohorts.

    L-Leucine → Human urinary 3-hydroxyisovaleric acid excretion source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/biotin-research/21918059.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "5cf1d7e25ae7bdfeb2ac3225cee8e4e660723d5197fc057f63327b3ad9eb3aaf", "start_char": 0, "end_char": 1723, "text_sha256": "5cf1d7e25ae7bdfeb2ac3225cee8e4e660723d5197fc057f63327b3ad9eb3aaf"}
    experimental_model
    Leucine challenge during biotin depletion in two cohorts of 5 and 7 healthy adults
    exposure
    28-day egg-white depletion; weekly oral leucine challenge
    limitations
    The challenge was sensitive but not diagnostically superior to 24-hour urine measurements; no validated universal threshold follows.
    nutrient_topic
    Biotin research collection; topical membership is not evidence of a direct dietary effect. · Biotin
    organism
    Homo sapiens
    plain_language
    Extra leucine made the impaired pathway easier to observe.
    primary_references
    [b7-p21918059] Urinary excretion of 3-hydroxyisovaleric acid and 3-hydroxyisovaleryl carnitine increases in response to a leucine challenge in marginally biotin-deficient humans. (2011). https://pubmed.ncbi.nlm.nih.gov/21918059/ DOI: 10.3945/jn.111.146126
    tissue_or_cell_type
    Urine
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Biotin: carboxylases, recycling, deficiency and nutrient interactions (2026-09-17) · lines 910–921

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Leucine challenge during biotin depletion in two cohorts of 5 and 7 healthy adults · source_derived_draft · unverified_draft

    ### b7-leucine-challenge-3hia Challenge-induced urinary 3-HIA rose more than twofold by day 14 in both biotin-depleted cohorts. Condition category: nutrient_deficiency nutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Extra leucine made the impaired pathway easier to observe. organism: Homo sapiens tissue_or_cell_type: Urine experimental_model: Leucine challenge during biotin depletion in two cohorts of 5 and 7 healthy adults limitations: The challenge was sensitive but not diagnostically superior to 24-hour urine measurements; no validated universal threshold follows. exposure: 28-day egg-white depletion; weekly oral leucine challenge evidence_span: {"source_cache": "artifacts/biotin-research/21918059.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "5cf1d7e25ae7bdfeb2ac3225cee8e4e660723d5197fc057f63327b3ad9eb3aaf", "start_char": 0, "end_char": 1723, "text_sha256": "5cf1d7e25ae7bdfeb2ac3225cee8e4e660723d5197fc057f63327b3ad9eb3aaf"} [b7-p21918059] Urinary excretion of 3-hydroxyisovaleric acid and 3-hydroxyisovaleryl carnitine increases in response to a leucine challenge in marginally biotin-deficient humans. (2011). https://pubmed.ncbi.nlm.nih.gov/21918059/ DOI: 10.3945/jn.111.146126
    Complete structured claim and evidence

  4. Active recombinant human MCC contained alpha and beta subunits at a one-to-one ratio.

    Human methylcrotonyl-CoA carboxylase alpha subunit / MCCC1 → Human methylcrotonyl-CoA carboxylase beta subunit / MCCC2 source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/biotin-research/17360195.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3ae046490d9657d005d5c39efb1f7439bc015d0cb2190834e3e868de70eaf985", "start_char": 0, "end_char": 1067, "text_sha256": "3ae046490d9657d005d5c39efb1f7439bc015d0cb2190834e3e868de70eaf985"}
    experimental_model
    Purified recombinant human MCC produced by baculovirus expression
    exposure
    ATP and methylcrotonyl-CoA kinetics
    limitations
    Recombinant-enzyme kinetics do not determine human dietary requirements.
    nutrient_topic
    Biotin research collection; topical membership is not evidence of a direct dietary effect. · Biotin
    organism
    Homo sapiens
    plain_language
    MCC needs both subunits; biotin cannot replace a missing protein partner.
    primary_references
    [b7-p17360195] Expression, purification, characterization of human 3-methylcrotonyl-CoA carboxylase (MCCC). (2007). https://pubmed.ncbi.nlm.nih.gov/17360195/ DOI: 10.1016/j.pep.2007.01.012
    tissue_or_cell_type
    Purified human MCC complex

    Biotin: carboxylases, recycling, deficiency and nutrient interactions (2026-09-17) · lines 767–778

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified recombinant human MCC produced by baculovirus expression · source_derived_draft · unverified_draft

    ### b7-mcc-complex Active recombinant human MCC contained alpha and beta subunits at a one-to-one ratio. Condition category: normal nutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect. plain_language: MCC needs both subunits; biotin cannot replace a missing protein partner. organism: Homo sapiens tissue_or_cell_type: Purified human MCC complex experimental_model: Purified recombinant human MCC produced by baculovirus expression limitations: Recombinant-enzyme kinetics do not determine human dietary requirements. exposure: ATP and methylcrotonyl-CoA kinetics evidence_span: {"source_cache": "artifacts/biotin-research/17360195.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3ae046490d9657d005d5c39efb1f7439bc015d0cb2190834e3e868de70eaf985", "start_char": 0, "end_char": 1067, "text_sha256": "3ae046490d9657d005d5c39efb1f7439bc015d0cb2190834e3e868de70eaf985"} [b7-p17360195] Expression, purification, characterization of human 3-methylcrotonyl-CoA carboxylase (MCCC). (2007). https://pubmed.ncbi.nlm.nih.gov/17360195/ DOI: 10.1016/j.pep.2007.01.012
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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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