Component
2-Amino-3-carboxymuconate 6-semialdehyde
ACMS; immediate HAAO ring-cleavage intermediate that can spontaneously cyclize to quinolinate.
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.
Where it participates (unsigned role)
Human HAAO expressed in HEK-293 cells was enzymatically active toward 3-hydroxyanthranilate, with an apparent substrate Km near 2 micromolar in the study of the quinolinate-producing pathway step.
Experimental context and source evidence
- cross_nutrient
- This step follows the canonical PLP-dependent KYNU reaction and uses a nonheme iron enzyme.
- evidence_span
- {"source_cache": "artifacts/niacin-precursors-sources/haao1994.abstract.txt", "locator": "Indexed primary abstract", "start_char": 0, "end_char": 1874, "file_sha256": "a79697b138bcb2957b0eff9580266c7879a1c5853aba34898f891559b4e435f8", "text_sha256": "a79697b138bcb2957b0eff9580266c7879a1c5853aba34898f891559b4e435f8"}
- experimental_model
- Human HAAO cDNA from HepG2 library, expressed in HEK-293 cells and assayed biochemically
- exposure
- Biochemical or structural assay; no dietary intervention
- limitations
- The immediate HAAO product is ACMS, which cyclizes to quinolinate; the indexed abstract uses pathway-level quinolinate wording. This claim does not assert direct NAD+ synthesis.
- nutrient_topic
- Niacin research collection; topical membership is not evidence of a direct dietary effect. · Niacin (vitamin B3)
- organism
- Homo sapiens
- plain_language
- Expressed human HAAO processed the product made by B6-dependent KYNU.
- primary_references
- [b3-pre-haao1994] Molecular cloning and functional expression of human 3-hydroxyanthranilic-acid dioxygenase. (1994). https://pubmed.ncbi.nlm.nih.gov/7514594/ DOI: 10.1016/s0021-9258(17)36717-0 [b3-pre-haao2017] Crystal structures of human 3-hydroxyanthranilate 3,4-dioxygenase with native and non-native metals bound in the active site. (2017). https://pubmed.ncbi.nlm.nih.gov/28375145/ DOI: 10.1107/s2059798317002029
- supporting_evidence_spans
- [{"source_cache": "artifacts/niacin-precursors-sources/haao2017.paragraphs.txt", "locator": "Normalized full-text paragraphs 14–14 (0-based)", "start_char": 4395, "end_char": 7197, "file_sha256": "d02386a59595104ccae2e62943e69030930da86ec005769b469f2001e31a6eb5", "text_sha256": "3b52b56d1b671c24721b47204cd30d19cd004f8a461fecd4875e94d3f491dbf6"}]
- tissue_or_cell_type
- HEK-293 cells expressing human HAAO; biochemical activity assay
Niacin: NAD metabolism, deficiency and nutrient interactions (2026-09-17) · lines 521–535
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human HAAO cDNA from HepG2 library, expressed in HEK-293 cells and assayed biochemically · source_derived_draft · unverified_draft
### b3-pre-haao-human-activity Human HAAO expressed in HEK-293 cells was enzymatically active toward 3-hydroxyanthranilate, with an apparent substrate Km near 2 micromolar in the study of the quinolinate-producing pathway step. Condition category: normal nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Expressed human HAAO processed the product made by B6-dependent KYNU. organism: Homo sapiens tissue_or_cell_type: HEK-293 cells expressing human HAAO; biochemical activity assay experimental_model: Human HAAO cDNA from HepG2 library, expressed in HEK-293 cells and assayed biochemically limitations: The immediate HAAO product is ACMS, which cyclizes to quinolinate; the indexed abstract uses pathway-level quinolinate wording. This claim does not assert direct NAD+ synthesis. exposure: Biochemical or structural assay; no dietary intervention cross_nutrient: This step follows the canonical PLP-dependent KYNU reaction and uses a nonheme iron enzyme. evidence_span: {"source_cache": "artifacts/niacin-precursors-sources/haao1994.abstract.txt", "locator": "Indexed primary abstract", "start_char": 0, "end_char": 1874, "file_sha256": "a79697b138bcb2957b0eff9580266c7879a1c5853aba34898f891559b4e435f8", "text_sha256": "a79697b138bcb2957b0eff9580266c7879a1c5853aba34898f891559b4e435f8"} supporting_evidence_spans: [{"source_cache": "artifacts/niacin-precursors-sources/haao2017.paragraphs.txt", "locator": "Normalized full-text paragraphs 14–14 (0-based)", "start_char": 4395, "end_char": 7197, "file_sha256": "d02386a59595104ccae2e62943e69030930da86ec005769b469f2001e31a6eb5", "text_sha256": "3b52b56d1b671c24721b47204cd30d19cd004f8a461fecd4875e94d3f491dbf6"}] [b3-pre-haao1994] Molecular cloning and functional expression of human 3-hydroxyanthranilic-acid dioxygenase. (1994). https://pubmed.ncbi.nlm.nih.gov/7514594/ DOI: 10.1016/s0021-9258(17)36717-0 [b3-pre-haao2017] Crystal structures of human 3-hydroxyanthranilate 3,4-dioxygenase with native and non-native metals bound in the active site. (2017). https://pubmed.ncbi.nlm.nih.gov/28375145/ DOI: 10.1107/s2059798317002029
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.