Component
Human kynureninase / KYNU
Human kynureninase / KYNU
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
Human KYNU cleaves 3-hydroxykynurenine to 3-hydroxyanthranilate and alanine using PLP.
Experimental context and source evidence
- cross_nutrient
- PLP-dependent KYNU follows the FAD-dependent KMO step, connecting B6 and B2 with tryptophan-niacin metabolism.
- existing_related_claim_ids
- ["5570a502-6ebf-5397-bf2a-0148727e7695"]
- experimental_model
- Recombinant human KYNU crystallography and biochemical characterization
- limitations
- KYNU does not directly make NAD; subsequent enzymes and dietary niacin also contribute.
- nutrient_topic
- Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
- organism
- Homo sapiens
- plain_language
- This B6-dependent step processes the product of upstream KMO chemistry.
- primary_references
- [b6-kynu-2007] Crystal Structure of Homo Sapiens Kynureninase (2007). https://pmc.ncbi.nlm.nih.gov/articles/PMC2531291/ DOI: 10.1021/bi0616697
- tissue_or_cell_type
- Purified recombinant protein; no intact tissue
Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 885–896
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human KYNU crystallography and biochemical characterization · source_derived_draft · unverified_draft
### b6-met-kynu-hydrolysis Human KYNU cleaves 3-hydroxykynurenine to 3-hydroxyanthranilate and alanine using PLP. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: This B6-dependent step processes the product of upstream KMO chemistry. organism: Homo sapiens tissue_or_cell_type: Purified recombinant protein; no intact tissue experimental_model: Recombinant human KYNU crystallography and biochemical characterization limitations: KYNU does not directly make NAD; subsequent enzymes and dietary niacin also contribute. cross_nutrient: PLP-dependent KYNU follows the FAD-dependent KMO step, connecting B6 and B2 with tryptophan-niacin metabolism. existing_related_claim_ids: ["5570a502-6ebf-5397-bf2a-0148727e7695"] [b6-kynu-2007] Crystal Structure of Homo Sapiens Kynureninase (2007). https://pmc.ncbi.nlm.nih.gov/articles/PMC2531291/ DOI: 10.1021/bi0616697
Complete structured claim and evidence
What acts on it
Human kynureninase crystallography resolves the PLP-containing active-site architecture.
Experimental context and source evidence
- cross_nutrient
- B6-dependent KYNU acts in the pathway leading from tryptophan toward niacin/NAD precursors.
- experimental_model
- Recombinant human KYNU crystallography and biochemical characterization
- limitations
- Purified-enzyme evidence does not define dietary requirements or cellular PLP thresholds.
- nutrient_topic
- Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
- organism
- Homo sapiens
- plain_language
- KYNU uses active B6 in the tryptophan pathway.
- primary_references
- [b6-kynu-2007] Crystal Structure of Homo Sapiens Kynureninase (2007). https://pmc.ncbi.nlm.nih.gov/articles/PMC2531291/ DOI: 10.1021/bi0616697
- tissue_or_cell_type
- Purified recombinant protein; no intact tissue
Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 873–883
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human KYNU crystallography and biochemical characterization · source_derived_draft · unverified_draft
### b6-met-kynu-plp Human kynureninase crystallography resolves the PLP-containing active-site architecture. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: KYNU uses active B6 in the tryptophan pathway. organism: Homo sapiens tissue_or_cell_type: Purified recombinant protein; no intact tissue experimental_model: Recombinant human KYNU crystallography and biochemical characterization limitations: Purified-enzyme evidence does not define dietary requirements or cellular PLP thresholds. cross_nutrient: B6-dependent KYNU acts in the pathway leading from tryptophan toward niacin/NAD precursors. [b6-kynu-2007] Crystal Structure of Homo Sapiens Kynureninase (2007). https://pmc.ncbi.nlm.nih.gov/articles/PMC2531291/ DOI: 10.1021/bi0616697
Complete structured claim and evidence
Where it participates (unsigned role)
The cohort also included homozygous KYNU p.V57Efs*21 and compound-heterozygous p.Y156*/p.F349Kfs*4 patients with reduced circulating NAD and multiple malformations.
Experimental context and source evidence
- availability_state
- machinery_impairment Imported condition classification; unverified.
- cross_nutrient
- Human kynureninase / KYNU (affected_enzyme); L-Tryptophan (upstream_precursor); Malformations in congenital NAD deficiency disorder (observed_phenotype)
- evidence_span
- {"source_cache": "artifacts/niacin-clinical-sources/shi2017.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "2c5dcc72d338ac41bd47e4363a149abc503859e2760398fed030f02d5891e2bb", "start_char": 0, "end_char": 1874, "text_sha256": "2c5dcc72d338ac41bd47e4363a149abc503859e2760398fed030f02d5891e2bb"}
- experimental_model
- Four patients from unrelated families; sequencing and circulating metabolites, with parallel enzyme and mouse experiments
- exposure
- Biallelic HAAO or KYNU loss-of-function variants
- limitations
- Rare inherited synthesis impairment is distinct from dietary shortage. Prevention with gestational niacin was demonstrated in mice, not as an established prenatal treatment in humans.
- nutrient_topic
- Niacin research collection; topical membership is not evidence of a direct dietary effect. · Niacin (vitamin B3)
- organism
- Homo sapiens
- plain_language
- KYNU is a second independent point where inherited failure can interrupt NAD production.
- primary_references
- [nia-clin-shi2017] NAD Deficiency, Congenital Malformations, and Niacin Supplementation. (2017). https://pubmed.ncbi.nlm.nih.gov/28792876/ DOI: 10.1056/nejmoa1616361
- tissue_or_cell_type
- Circulation and congenital organ development
- trigger_kind
- machinery_impairment Imported condition classification; unverified.
Niacin: NAD metabolism, deficiency and nutrient interactions (2026-09-17) · lines 1249–1261
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Four patients from unrelated families; sequencing and circulating metabolites, with parallel enzyme and mouse experiments · source_derived_draft · unverified_draft
### nia-clin-kynu-human-low-nad The cohort also included homozygous KYNU p.V57Efs*21 and compound-heterozygous p.Y156*/p.F349Kfs*4 patients with reduced circulating NAD and multiple malformations. Condition category: machinery_impairment nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: KYNU is a second independent point where inherited failure can interrupt NAD production. organism: Homo sapiens tissue_or_cell_type: Circulation and congenital organ development experimental_model: Four patients from unrelated families; sequencing and circulating metabolites, with parallel enzyme and mouse experiments limitations: Rare inherited synthesis impairment is distinct from dietary shortage. Prevention with gestational niacin was demonstrated in mice, not as an established prenatal treatment in humans. exposure: Biallelic HAAO or KYNU loss-of-function variants cross_nutrient: Human kynureninase / KYNU (affected_enzyme); L-Tryptophan (upstream_precursor); Malformations in congenital NAD deficiency disorder (observed_phenotype) evidence_span: {"source_cache": "artifacts/niacin-clinical-sources/shi2017.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "2c5dcc72d338ac41bd47e4363a149abc503859e2760398fed030f02d5891e2bb", "start_char": 0, "end_char": 1874, "text_sha256": "2c5dcc72d338ac41bd47e4363a149abc503859e2760398fed030f02d5891e2bb"} [nia-clin-shi2017] NAD Deficiency, Congenital Malformations, and Niacin Supplementation. (2017). https://pubmed.ncbi.nlm.nih.gov/28792876/ DOI: 10.1056/nejmoa1616361
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.