Component
MMACHC-catalyzed alkylcobalamin dealkylation
MMACHC-catalyzed alkylcobalamin dealkylation
1 recorded relationships. Experimental role, claim status and evidence remain attached to each record.
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.
Other things that act on it
Enzymes, hormones, genes, and other components with a recorded effect. These are not nutrients, so they do not count toward the arrows above. Each finding names the chapter that recorded it.
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.
What acts on it
In the human MMACHC dealkylation study, cysteine and homocysteine did not substitute for glutathione as the thiol co-substrate.
Experimental context and source evidence
- cross_nutrient
- true
- evidence_location
- Primary abstract; indexed article Introduction/Figure 1
- experimental_model
- Purified human MMACHC thiol substitution assays
- exposure
- GSH versus cysteine or homocysteine
- limitations
- No implication that cysteine availability is irrelevant to cellular GSH synthesis; that upstream pathway was not tested here.
- nutrient_topic
- Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
- organism
- Homo sapiens
- plain_language
- Having a thiol group was not enough; the enzyme required glutathione in these assays.
- primary_references
- [kim-2009-gsh-dealkylation] A human vitamin B12 trafficking protein uses glutathione transferase activity for processing alkylcobalamins (2009). https://pubmed.ncbi.nlm.nih.gov/19801555/ DOI: 10.1074/jbc.M109.057877
- tissue_or_cell_type
- Cell-free assay
Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 739–751
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified human MMACHC thiol substitution assays · source_derived_draft · unverified_draft
### b12-mmachc-thiol-specificity In the human MMACHC dealkylation study, cysteine and homocysteine did not substitute for glutathione as the thiol co-substrate. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Having a thiol group was not enough; the enzyme required glutathione in these assays. organism: Homo sapiens tissue_or_cell_type: Cell-free assay experimental_model: Purified human MMACHC thiol substitution assays limitations: No implication that cysteine availability is irrelevant to cellular GSH synthesis; that upstream pathway was not tested here. exposure: GSH versus cysteine or homocysteine cross_nutrient: true evidence_location: Primary abstract; indexed article Introduction/Figure 1 [kim-2009-gsh-dealkylation] A human vitamin B12 trafficking protein uses glutathione transferase activity for processing alkylcobalamins (2009). https://pubmed.ncbi.nlm.nih.gov/19801555/ DOI: 10.1074/jbc.M109.057877
Complete structured claim and evidence
The events it takes part in
A mechanism often involves more than two components. These are the full events, with every participant and its role.
Situations it appears in
Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.
In the sources
Preserved passages that mention this component, quoted exactly. Open one to read it in context.
Open hypotheses
Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.
This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.