Component

Human MMAA GTPase

Human MMAA GTPase

7 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. The human MMUT-MMAA structure showed MMAA stabilizing a roughly 180-degree rotation that exposed the MMUT B12-binding domain.

    Human MMAA GTPase → Exposure of the human MMUT cobalamin-binding domain source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    false
    evidence_location
    Full text Results; Figures 2-4; cofactor off-loading and MMUT activity Methods
    experimental_model
    Purified human proteins
    exposure
    Crystallized complex with CoA, GDP and Mg2+
    limitations
    Static structure; does not directly measure the complete loading trajectory.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    The human-protein structure showed how MMAA opens access to MMUT-bound B12.
    primary_references
    [mascarenhas-2023-nanoassembly] Architecture of the human G-protein-methylmalonyl-CoA mutase nanoassembly for B12 delivery and repair. (2023). https://pubmed.ncbi.nlm.nih.gov/37468522/ DOI: 10.1038/s41467-023-40077-4
    tissue_or_cell_type
    Purified protein assay

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1117–1129

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

    ### mmaa-exposes-mmut-cobalamin-domain The human MMUT-MMAA structure showed MMAA stabilizing a roughly 180-degree rotation that exposed the MMUT B12-binding domain. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: The human-protein structure showed how MMAA opens access to MMUT-bound B12. organism: Homo sapiens tissue_or_cell_type: Purified protein assay experimental_model: Purified human proteins limitations: Static structure; does not directly measure the complete loading trajectory. exposure: Crystallized complex with CoA, GDP and Mg2+ cross_nutrient: false evidence_location: Full text Results; Figures 2-4; cofactor off-loading and MMUT activity Methods [mascarenhas-2023-nanoassembly] Architecture of the human G-protein-methylmalonyl-CoA mutase nanoassembly for B12 delivery and repair. (2023). https://pubmed.ncbi.nlm.nih.gov/37468522/ DOI: 10.1038/s41467-023-40077-4
    Complete structured claim and evidence

  2. Purified human MMAA displayed intrinsic GTPase activity modulated by human MMUT.

    Human MMAA GTPase → Guanosine triphosphate source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    false
    evidence_location
    Indexed primary abstract; indexed Results
    experimental_model
    Purified human proteins
    exposure
    GTP hydrolysis assay
    limitations
    Biochemical reconstitution; does not determine cellular rate or dietary requirement.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    Human MMAA consumed GTP in the protein assay, linking energy use to B12 handling.
    primary_references
    [froese-2010-human-mmaa] Structures of the human GTPase MMAA and vitamin B12-dependent methylmalonyl-CoA mutase and insight into their complex formation. (2010). https://pubmed.ncbi.nlm.nih.gov/20876572/ DOI: 10.1074/jbc.m110.177717
    tissue_or_cell_type
    Purified protein assay

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1033–1045

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

    ### mmaa-hydrolyzes-gtp Purified human MMAA displayed intrinsic GTPase activity modulated by human MMUT. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Human MMAA consumed GTP in the protein assay, linking energy use to B12 handling. organism: Homo sapiens tissue_or_cell_type: Purified protein assay experimental_model: Purified human proteins limitations: Biochemical reconstitution; does not determine cellular rate or dietary requirement. exposure: GTP hydrolysis assay cross_nutrient: false evidence_location: Indexed primary abstract; indexed Results [froese-2010-human-mmaa] Structures of the human GTPase MMAA and vitamin B12-dependent methylmalonyl-CoA mutase and insight into their complex formation. (2010). https://pubmed.ncbi.nlm.nih.gov/20876572/ DOI: 10.1074/jbc.m110.177717
    Complete structured claim and evidence

  3. A human MMAA/MMAB repair mixture with GTP and ATP transferred cob(II)alamin from MMUT to MMAB in anaerobic spectroscopy.

    Human MMAA GTPase → Cob(II)alamin off-loading from human MMUT source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    false
    evidence_location
    Full text Results; Figures 2-4; cofactor off-loading and MMUT activity Methods
    experimental_model
    Purified human proteins
    exposure
    Anaerobic assay; MMAB, MMAA, GTP and ATP
    limitations
    Reconstituted transfer; spectroscopy reports cofactor environment, not cellular turnover.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    In the purified repair assay, inactive B12 moved from MMUT back to MMAB.
    primary_references
    [mascarenhas-2023-nanoassembly] Architecture of the human G-protein-methylmalonyl-CoA mutase nanoassembly for B12 delivery and repair. (2023). https://pubmed.ncbi.nlm.nih.gov/37468522/ DOI: 10.1038/s41467-023-40077-4
    tissue_or_cell_type
    Purified protein assay

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1131–1143

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

    ### mmaa-mmab-offload-cob-ii A human MMAA/MMAB repair mixture with GTP and ATP transferred cob(II)alamin from MMUT to MMAB in anaerobic spectroscopy. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: In the purified repair assay, inactive B12 moved from MMUT back to MMAB. organism: Homo sapiens tissue_or_cell_type: Purified protein assay experimental_model: Purified human proteins limitations: Reconstituted transfer; spectroscopy reports cofactor environment, not cellular turnover. exposure: Anaerobic assay; MMAB, MMAA, GTP and ATP cross_nutrient: false evidence_location: Full text Results; Figures 2-4; cofactor off-loading and MMUT activity Methods [mascarenhas-2023-nanoassembly] Architecture of the human G-protein-methylmalonyl-CoA mutase nanoassembly for B12 delivery and repair. (2023). https://pubmed.ncbi.nlm.nih.gov/37468522/ DOI: 10.1038/s41467-023-40077-4
    Complete structured claim and evidence

  4. Human MMAA formed a stable complex preferentially with apo-MMUT and with GMPPNP rather than GDP.

    Human MMAA GTPase → Human methylmalonyl-CoA mutase / MMUT source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    false
    evidence_location
    Indexed primary abstract; indexed Results
    experimental_model
    Purified human proteins
    exposure
    Apo versus holo-MMUT; GMPPNP versus GDP
    limitations
    GMPPNP is a GTP analogue; stable-complex abundance is not cofactor transfer rate.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    The purified human proteins assembled differently depending on MMUT cofactor occupancy and nucleotide state.
    primary_references
    [froese-2010-human-mmaa] Structures of the human GTPase MMAA and vitamin B12-dependent methylmalonyl-CoA mutase and insight into their complex formation. (2010). https://pubmed.ncbi.nlm.nih.gov/20876572/ DOI: 10.1074/jbc.m110.177717
    tissue_or_cell_type
    Purified protein assay

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1047–1059

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

    ### mmaa-prefers-apo-mmut-complex Human MMAA formed a stable complex preferentially with apo-MMUT and with GMPPNP rather than GDP. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: The purified human proteins assembled differently depending on MMUT cofactor occupancy and nucleotide state. organism: Homo sapiens tissue_or_cell_type: Purified protein assay experimental_model: Purified human proteins limitations: GMPPNP is a GTP analogue; stable-complex abundance is not cofactor transfer rate. exposure: Apo versus holo-MMUT; GMPPNP versus GDP cross_nutrient: false evidence_location: Indexed primary abstract; indexed Results [froese-2010-human-mmaa] Structures of the human GTPase MMAA and vitamin B12-dependent methylmalonyl-CoA mutase and insight into their complex formation. (2010). https://pubmed.ncbi.nlm.nih.gov/20876572/ DOI: 10.1074/jbc.m110.177717
    Complete structured claim and evidence

  5. Adding human MMAA at reaction initiation protected recombinant human MMUT against catalytic inactivation.

    Human MMAA GTPase → Human methylmalonyl-CoA mutase / MMUT source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    false
    evidence_location
    Indexed primary abstract
    experimental_model
    Purified human proteins
    exposure
    MMAA added at reaction initiation
    limitations
    Biochemical reconstitution; does not determine cellular rate or dietary requirement.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    MMAA helped purified human MMUT remain active during the tested reaction.
    primary_references
    [takahashi-2010-mmaa-repair] Protection and reactivation of human methylmalonyl-CoA mutase by MMAA protein. (2011). https://pubmed.ncbi.nlm.nih.gov/21138732/ DOI: 10.1016/j.bbrc.2010.11.141
    tissue_or_cell_type
    Purified protein assay

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1075–1087

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

    ### mmaa-protects-mmut-activity Adding human MMAA at reaction initiation protected recombinant human MMUT against catalytic inactivation. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: MMAA helped purified human MMUT remain active during the tested reaction. organism: Homo sapiens tissue_or_cell_type: Purified protein assay experimental_model: Purified human proteins limitations: Biochemical reconstitution; does not determine cellular rate or dietary requirement. exposure: MMAA added at reaction initiation cross_nutrient: false evidence_location: Indexed primary abstract [takahashi-2010-mmaa-repair] Protection and reactivation of human methylmalonyl-CoA mutase by MMAA protein. (2011). https://pubmed.ncbi.nlm.nih.gov/21138732/ DOI: 10.1016/j.bbrc.2010.11.141
    Complete structured claim and evidence

  6. Adding MMAA after 60 minutes restored activity in an inactivated human MMUT reaction through GTP hydrolysis.

    Human MMAA GTPase → Human methylmalonyl-CoA mutase / MMUT source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    false
    evidence_location
    Indexed primary abstract
    experimental_model
    Purified human proteins
    exposure
    MMAA added after 60-minute catalytic inactivation
    limitations
    In-vitro reactivation; abstract interprets damaged-cofactor exchange rather than measuring every intermediate.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    MMAA restarted an inactive purified human MMUT reaction in a GTP-dependent assay.
    primary_references
    [takahashi-2010-mmaa-repair] Protection and reactivation of human methylmalonyl-CoA mutase by MMAA protein. (2011). https://pubmed.ncbi.nlm.nih.gov/21138732/ DOI: 10.1016/j.bbrc.2010.11.141
    tissue_or_cell_type
    Purified protein assay

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1089–1101

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

    ### mmaa-reactivates-mmut Adding MMAA after 60 minutes restored activity in an inactivated human MMUT reaction through GTP hydrolysis. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: MMAA restarted an inactive purified human MMUT reaction in a GTP-dependent assay. organism: Homo sapiens tissue_or_cell_type: Purified protein assay experimental_model: Purified human proteins limitations: In-vitro reactivation; abstract interprets damaged-cofactor exchange rather than measuring every intermediate. exposure: MMAA added after 60-minute catalytic inactivation cross_nutrient: false evidence_location: Indexed primary abstract [takahashi-2010-mmaa-repair] Protection and reactivation of human methylmalonyl-CoA mutase by MMAA protein. (2011). https://pubmed.ncbi.nlm.nih.gov/21138732/ DOI: 10.1016/j.bbrc.2010.11.141
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Under anaerobic conditions, ADP reduced the rate of cob(II)alamin transfer from human MMUT to MMAB in the MMAA repair system.

    Adenosine diphosphate → Cob(II)alamin off-loading from human MMUT source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    false
    evidence_location
    Full text Results; Figures 2-3, Table 3
    experimental_model
    Purified human proteins
    exposure
    Anaerobic cofactor-transfer assay with ADP
    limitations
    Transfer rate differs from oxidation protection; methylmalonyl-CoA reversed ADP inhibition in this assay.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    When oxidation was excluded, ADP slowed transfer of inactive B12 between the purified human proteins.
    primary_references
    [gouda-2023-adp-repair] Bivalent molecular mimicry by ADP protects metal redox state and promotes coenzyme B12 repair. (2023). https://pubmed.ncbi.nlm.nih.gov/36888659/ DOI: 10.1073/pnas.2220677120
    tissue_or_cell_type
    Purified protein assay

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1412–1424

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

    ### adp-slows-mmut-cob-ii-offloading Under anaerobic conditions, ADP reduced the rate of cob(II)alamin transfer from human MMUT to MMAB in the MMAA repair system. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: When oxidation was excluded, ADP slowed transfer of inactive B12 between the purified human proteins. organism: Homo sapiens tissue_or_cell_type: Purified protein assay experimental_model: Purified human proteins limitations: Transfer rate differs from oxidation protection; methylmalonyl-CoA reversed ADP inhibition in this assay. exposure: Anaerobic cofactor-transfer assay with ADP cross_nutrient: false evidence_location: Full text Results; Figures 2-3, Table 3 [gouda-2023-adp-repair] Bivalent molecular mimicry by ADP protects metal redox state and promotes coenzyme B12 repair. (2023). https://pubmed.ncbi.nlm.nih.gov/36888659/ DOI: 10.1073/pnas.2220677120
    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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