Component
Human quinolinate phosphoribosyltransferase / QPRT
Human enzyme converting quinolinate and PRPP to NaMN.
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 it acts on
Human QPRT converts quinolinate and PRPP toward nicotinic acid mononucleotide; the human enzyme structures resolve reactant quinolinate and product NaMN complexes.
Experimental context and source evidence
- evidence_span
- {"source_cache": "artifacts/niacin-precursors-sources/qprt2016.paragraphs.txt", "locator": "Normalized full-text paragraphs 13–15 (0-based)", "start_char": 10597, "end_char": 15612, "file_sha256": "85fcc4a79a17f4f3846301f67698a444c3c9930829e167d86a96adbb72d830e6", "text_sha256": "8da78d25a53af6507018eece4ce553705dc505d0b169f678affad49ee21b10f6"}
- experimental_model
- Purified recombinant human QPRT crystallography, calorimetry and oligomer studies
- exposure
- Biochemical or structural assay; no dietary intervention
- limitations
- Structural and biochemical enzyme study; does not establish how much dietary tryptophan becomes NAD in a person.
- nutrient_topic
- Niacin research collection; topical membership is not evidence of a direct dietary effect. · Niacin (vitamin B3)
- organism
- Homo sapiens
- plain_language
- Quinolinate enters the same deamidated mononucleotide route used by nicotinic acid.
- primary_references
- [b3-pre-qprt2016] Structural Insights into the Quaternary Catalytic Mechanism of Hexameric Human Quinolinate Phosphoribosyltransferase, a Key Enzyme in de novo NAD Biosynthesis. (2016). https://pubmed.ncbi.nlm.nih.gov/26805589/ DOI: 10.1038/srep19681
- supporting_evidence_spans
- [{"source_cache": "artifacts/niacin-precursors-sources/qprt2016.paragraphs.txt", "locator": "Normalized full-text paragraphs 4–4 (0-based)", "start_char": 1453, "end_char": 3871, "file_sha256": "85fcc4a79a17f4f3846301f67698a444c3c9930829e167d86a96adbb72d830e6", "text_sha256": "be14ed97ccf53b635f2cb35969188ce42c84dd739db897a24cbf3e65d8a3e3d1"}]
- tissue_or_cell_type
- Purified recombinant protein; no intact tissue
Niacin: NAD metabolism, deficiency and nutrient interactions (2026-09-17) · lines 537–549
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified recombinant human QPRT crystallography, calorimetry and oligomer studies · source_derived_draft · unverified_draft
### b3-pre-qprt-namn Human QPRT converts quinolinate and PRPP toward nicotinic acid mononucleotide; the human enzyme structures resolve reactant quinolinate and product NaMN complexes. Condition category: normal nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Quinolinate enters the same deamidated mononucleotide route used by nicotinic acid. organism: Homo sapiens tissue_or_cell_type: Purified recombinant protein; no intact tissue experimental_model: Purified recombinant human QPRT crystallography, calorimetry and oligomer studies limitations: Structural and biochemical enzyme study; does not establish how much dietary tryptophan becomes NAD in a person. exposure: Biochemical or structural assay; no dietary intervention evidence_span: {"source_cache": "artifacts/niacin-precursors-sources/qprt2016.paragraphs.txt", "locator": "Normalized full-text paragraphs 13–15 (0-based)", "start_char": 10597, "end_char": 15612, "file_sha256": "85fcc4a79a17f4f3846301f67698a444c3c9930829e167d86a96adbb72d830e6", "text_sha256": "8da78d25a53af6507018eece4ce553705dc505d0b169f678affad49ee21b10f6"} supporting_evidence_spans: [{"source_cache": "artifacts/niacin-precursors-sources/qprt2016.paragraphs.txt", "locator": "Normalized full-text paragraphs 4–4 (0-based)", "start_char": 1453, "end_char": 3871, "file_sha256": "85fcc4a79a17f4f3846301f67698a444c3c9930829e167d86a96adbb72d830e6", "text_sha256": "be14ed97ccf53b635f2cb35969188ce42c84dd739db897a24cbf3e65d8a3e3d1"}] [b3-pre-qprt2016] Structural Insights into the Quaternary Catalytic Mechanism of Hexameric Human Quinolinate Phosphoribosyltransferase, a Key Enzyme in de novo NAD Biosynthesis. (2016). https://pubmed.ncbi.nlm.nih.gov/26805589/ DOI: 10.1038/srep19681
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.