Component
DIO3
Independent protein record for Iodothyronine deiodinase 3.
3 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 it acts on
DIO3 catalyzes inner-ring deiodination of T4 to reverse T3 in functional placental-enzyme studies.
Experimental context and source evidence
- experimental_model
- Human placental DIO3 cloning and functional expression.
- limitations
- This experiment-specific relationship does not establish a human dietary-deficiency threshold or supplementation benefit.
- organism
- Human placental protein in an expression system
Selenium: literature corrections and mechanism additions · lines 1020–1029
Metabolic Ledger literature curation, 17 September 2026; primary papers linked individually · supports · Human placental DIO3 cloning and functional expression. · secondary_verified · secondary_verified
## dio3-thyroxine-inactivation DIO3 lowers thyroid-hormone activity by converting T4 to reverse T3. DIO3 catalyzes inner-ring deiodination of T4 to reverse T3 in functional placental-enzyme studies. Experimental model: Human placental DIO3 cloning and functional expression. Organism: Human placental protein in an expression system Limitations: This experiment-specific relationship does not establish a human dietary-deficiency threshold or supplementation benefit. Primary reference: [Type 3 iodothyronine deiodinase: cloning, in vitro expression, and functional analysis of the placental selenoenzyme](https://www.jci.org/articles/view/118299)
Complete structured claim and evidenceDIO3 catalyzes inner-ring deiodination of T3 to 3,3-prime-T2 in functional placental-enzyme studies.
Experimental context and source evidence
- experimental_model
- Human placental DIO3 cloning and functional expression.
- limitations
- This experiment-specific relationship does not establish a human dietary-deficiency threshold or supplementation benefit.
- organism
- Human placental protein in an expression system
Selenium: literature corrections and mechanism additions · lines 1031–1040
Metabolic Ledger literature curation, 17 September 2026; primary papers linked individually · supports · Human placental DIO3 cloning and functional expression. · secondary_verified · secondary_verified
## dio3-triiodothyronine-inactivation DIO3 lowers thyroid-hormone activity by converting T3 to 3,3-prime-T2. DIO3 catalyzes inner-ring deiodination of T3 to 3,3-prime-T2 in functional placental-enzyme studies. Experimental model: Human placental DIO3 cloning and functional expression. Organism: Human placental protein in an expression system Limitations: This experiment-specific relationship does not establish a human dietary-deficiency threshold or supplementation benefit. Primary reference: [Type 3 iodothyronine deiodinase: cloning, in vitro expression, and functional analysis of the placental selenoenzyme](https://www.jci.org/articles/view/118299)
Complete structured claim and evidence
What acts on it
The 3-prime-untranslated-region SECIS element was required for expression of cloned human placental DIO3, which incorporated 75Se in transfected cells.
Experimental context and source evidence
- cross_nutrient
- Selenium incorporation supports an enzyme that inactivates iodine-containing hormones.
- evidence_locator
- Primary abstract
- evidence_spans
- [{"source_document": "artifacts/iodine-metabolism-sources/7593630.json", "source_field": "resultList.result[0].abstractText", "start_char": 0, "end_char": 1405}]
- experimental_model
- Human placental DIO3 cDNA and heterologous expression, selenium labeling and SECIS manipulation
- exposure
- Cloned 2.1-kb DIO3 cDNA; 75Se labeling and SECIS-dependent expression.
- limitations
- Expression machinery experiment; not evidence for selenium dosing in pregnancy.
- nutrient_topic
- Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine
- organism
- Human placental protein in transfected cells
- plain_language
- The hormone-inactivating enzyme also needs the cellular system that incorporates selenium into proteins.
- primary_references
- [i-met-7593630] Type 3 lodothyronine deiodinase: cloning, in vitro expression, and functional analysis of the placental selenoenzyme. (1995). https://pubmed.ncbi.nlm.nih.gov/7593630/ DOI: 10.1172/jci118299
- tissue_or_cell_type
- DIO3 expression system
Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1129–1142
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human placental DIO3 cDNA and heterologous expression, selenium labeling and SECIS manipulation · source_derived_draft · unverified_draft
### i-met-dio3-secis-expression The 3-prime-untranslated-region SECIS element was required for expression of cloned human placental DIO3, which incorporated 75Se in transfected cells. Condition category: normal nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The hormone-inactivating enzyme also needs the cellular system that incorporates selenium into proteins. organism: Human placental protein in transfected cells tissue_or_cell_type: DIO3 expression system experimental_model: Human placental DIO3 cDNA and heterologous expression, selenium labeling and SECIS manipulation limitations: Expression machinery experiment; not evidence for selenium dosing in pregnancy. exposure: Cloned 2.1-kb DIO3 cDNA; 75Se labeling and SECIS-dependent expression. cross_nutrient: Selenium incorporation supports an enzyme that inactivates iodine-containing hormones. evidence_locator: Primary abstract evidence_spans: [{"source_document": "artifacts/iodine-metabolism-sources/7593630.json", "source_field": "resultList.result[0].abstractText", "start_char": 0, "end_char": 1405}] [i-met-7593630] Type 3 lodothyronine deiodinase: cloning, in vitro expression, and functional analysis of the placental selenoenzyme. (1995). https://pubmed.ncbi.nlm.nih.gov/7593630/ DOI: 10.1172/jci118299
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.