Component

Human ATP:cob(I)alamin adenosyltransferase / MMAB

Human ATP:cob(I)alamin adenosyltransferase / MMAB

5 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. Purified human MMAB uses ATP to adenosylate cob(I)alamin to adenosylcobalamin.

    Human ATP:cob(I)alamin adenosyltransferase / MMAB → Cob(I)alamin source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    false
    evidence_location
    Indexed primary abstract
    experimental_model
    Purified human proteins
    exposure
    Cob(I)alamin and ATP
    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
    In a purified human-protein assay, MMAB made the B12 cofactor used by MMUT.
    primary_references
    [leal-2004-human-mmab] Human ATP:Cob(I)alamin adenosyltransferase and its interaction with methionine synthase reductase. (2004). https://pubmed.ncbi.nlm.nih.gov/15347655/ DOI: 10.1074/jbc.m405449200
    tissue_or_cell_type
    Purified protein assay

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 977–989

    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

    ### mmab-adenosylates-cob-i Purified human MMAB uses ATP to adenosylate cob(I)alamin to adenosylcobalamin. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: In a purified human-protein assay, MMAB made the B12 cofactor used by MMUT. 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: Cob(I)alamin and ATP cross_nutrient: false evidence_location: Indexed primary abstract [leal-2004-human-mmab] Human ATP:Cob(I)alamin adenosyltransferase and its interaction with methionine synthase reductase. (2004). https://pubmed.ncbi.nlm.nih.gov/15347655/ DOI: 10.1074/jbc.m405449200
    Complete structured claim and evidence

What acts on it

  1. Human [2Fe-2S] ferredoxin FDX1 supplied electrons for MMAB-dependent adenosylcobalamin synthesis in the FDXR/NADPH reconstitution.

    Human adrenodoxin / FDX1 → Human ATP:cob(I)alamin adenosyltransferase / MMAB source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    true
    evidence_location
    Abstract and indexed primary Results, Figure 3
    experimental_model
    Purified human proteins
    exposure
    FDX1, FDXR and NADPH with MMAB, cob(II)alamin and ATP
    limitations
    Biochemically competent donor; exclusivity or necessity in living humans was not tested.
    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 human system, an iron-sulfur electron carrier supported B12 activation.
    primary_references
    [gouda-2023-mmab-redox] Coordination Chemistry Controls Coenzyme B12 Synthesis by Human Adenosine Triphosphate:Cob(I)alamin Adenosyltransferase. (2023). https://pubmed.ncbi.nlm.nih.gov/37526260/ DOI: 10.1021/acs.inorgchem.3c02163
    tissue_or_cell_type
    Purified protein assay

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1005–1017

    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

    ### fdx1-supports-mmab Human [2Fe-2S] ferredoxin FDX1 supplied electrons for MMAB-dependent adenosylcobalamin synthesis in the FDXR/NADPH reconstitution. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: In the purified human system, an iron-sulfur electron carrier supported B12 activation. organism: Homo sapiens tissue_or_cell_type: Purified protein assay experimental_model: Purified human proteins limitations: Biochemically competent donor; exclusivity or necessity in living humans was not tested. exposure: FDX1, FDXR and NADPH with MMAB, cob(II)alamin and ATP cross_nutrient: true evidence_location: Abstract and indexed primary Results, Figure 3 [gouda-2023-mmab-redox] Coordination Chemistry Controls Coenzyme B12 Synthesis by Human Adenosine Triphosphate:Cob(I)alamin Adenosyltransferase. (2023). https://pubmed.ncbi.nlm.nih.gov/37526260/ DOI: 10.1021/acs.inorgchem.3c02163
    Complete structured claim and evidence

  2. Purified human MTRR coupled cob(II)alamin reduction to MMAB-dependent adenosylcobalamin synthesis in vitro.

    Methionine synthase reductase / MTRR → Human ATP:cob(I)alamin adenosyltransferase / MMAB source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    true
    evidence_location
    Indexed primary abstract
    experimental_model
    Purified human proteins
    exposure
    Purified MTRR plus MMAB and reductants
    limitations
    MTRR coupling in vitro does not identify the physiological mitochondrial electron donor.
    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 MTRR supported B12 activation in a test-tube system; this does not establish its mitochondrial role.
    primary_references
    [leal-2004-human-mmab] Human ATP:Cob(I)alamin adenosyltransferase and its interaction with methionine synthase reductase. (2004). https://pubmed.ncbi.nlm.nih.gov/15347655/ DOI: 10.1074/jbc.m405449200
    tissue_or_cell_type
    Purified protein assay

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 991–1003

    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

    ### mtrr-supports-mmab-in-vitro Purified human MTRR coupled cob(II)alamin reduction to MMAB-dependent adenosylcobalamin synthesis in vitro. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Human MTRR supported B12 activation in a test-tube system; this does not establish its mitochondrial role. organism: Homo sapiens tissue_or_cell_type: Purified protein assay experimental_model: Purified human proteins limitations: MTRR coupling in vitro does not identify the physiological mitochondrial electron donor. exposure: Purified MTRR plus MMAB and reductants cross_nutrient: true evidence_location: Indexed primary abstract [leal-2004-human-mmab] Human ATP:Cob(I)alamin adenosyltransferase and its interaction with methionine synthase reductase. (2004). https://pubmed.ncbi.nlm.nih.gov/15347655/ DOI: 10.1074/jbc.m405449200
    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

  2. 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

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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