Component
HIF-1 alpha prolyl hydroxylation
Hydroxylation of HIF-1 alpha oxygen-dependent degradation-domain proline residues; peptide assays are specified.
2 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
Reduced glutathione stimulated all three tested PHD isoforms in the absence of ascorbate; millimolar GSH could substitute in the peptide assay, indicating reductant redundancy in this setting.
Experimental context and source evidence
- cross_nutrient
- true
- evidence_location
- Figure 2A–B; hydroxylation Methods
- experimental_model
- Recombinant human PHD enzymes; HIF-1 alpha 556–574 peptide hydroxylation detected by VHL/elongin B/C binding
- exposure
- 10 µM FeSO4, 0.5 mM 2-oxoglutarate, pH 7.5, room temperature, 1 h; ascorbate omission/titration and GSH titration; standard ascorbate 2 mM.
- limitations
- Alternative reductant effects vary with substrate and assay; this is not a nutritional substitution recommendation or proof of in-vivo compensation mechanism.
- nutrient_topic
- Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
- organism
- Homo sapiens proteins
- plain_language
- These oxygen-sensing enzymes could use support from glutathione when vitamin C was absent in the test tube.
- primary_references
- [c-reg-nytko] Vitamin C is dispensable for oxygen sensing in vivo. (2011). https://pubmed.ncbi.nlm.nih.gov/21346252/ DOI: 10.1182/blood-2010-09-307637
- tissue_or_cell_type
- Cell-free
Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1145–1157
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human PHD enzymes; HIF-1 alpha 556–574 peptide hydroxylation detected by VHL/elongin B/C binding · source_derived_draft · unverified_draft
### c-reg-gsh-substitutes-phd Reduced glutathione stimulated all three tested PHD isoforms in the absence of ascorbate; millimolar GSH could substitute in the peptide assay, indicating reductant redundancy in this setting. Condition category: normal nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: These oxygen-sensing enzymes could use support from glutathione when vitamin C was absent in the test tube. organism: Homo sapiens proteins tissue_or_cell_type: Cell-free experimental_model: Recombinant human PHD enzymes; HIF-1 alpha 556–574 peptide hydroxylation detected by VHL/elongin B/C binding limitations: Alternative reductant effects vary with substrate and assay; this is not a nutritional substitution recommendation or proof of in-vivo compensation mechanism. exposure: 10 µM FeSO4, 0.5 mM 2-oxoglutarate, pH 7.5, room temperature, 1 h; ascorbate omission/titration and GSH titration; standard ascorbate 2 mM. cross_nutrient: true evidence_location: Figure 2A–B; hydroxylation Methods [c-reg-nytko] Vitamin C is dispensable for oxygen sensing in vivo. (2011). https://pubmed.ncbi.nlm.nih.gov/21346252/ DOI: 10.1182/blood-2010-09-307637
Complete structured claim and evidenceAscorbate increased the initial rate and extent of PHD2-catalyzed hydroxylation at both tested human HIF-1 alpha prolyl sites in purified-enzyme peptide experiments.
Experimental context and source evidence
- cross_nutrient
- true
- evidence_location
- Primary abstract rate/extent and substrate comparisons
- experimental_model
- Purified enzyme with human HIF-1 alpha-derived peptide substrate
- exposure
- Ascorbate versus omission/alternative reducing agents; exact concentrations and enzyme constructs not recovered from primary abstract.
- limitations
- Peptide hydroxylation does not directly establish HIF degradation or transcription changes in intact cells; ankyrin probe is not physiological HIF.
- nutrient_topic
- Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C
- organism
- Human HIF-1 alpha substrate; purified recombinant hydroxylase
- plain_language
- Vitamin C increased the activity of an isolated oxygen-sensing proline hydroxylase.
- primary_references
- [c-reg-flashman] Investigating the dependence of the hypoxia-inducible factor hydroxylases (factor inhibiting HIF and prolyl hydroxylase domain 2) on ascorbate and other reducing agents. (2010). https://pubmed.ncbi.nlm.nih.gov/20055761/ DOI: 10.1042/bj20091609
- tissue_or_cell_type
- Cell-free
Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1117–1129
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified enzyme with human HIF-1 alpha-derived peptide substrate · source_derived_draft · unverified_draft
### c-reg-phd2-ascorbate Ascorbate increased the initial rate and extent of PHD2-catalyzed hydroxylation at both tested human HIF-1 alpha prolyl sites in purified-enzyme peptide experiments. Condition category: normal nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: Vitamin C increased the activity of an isolated oxygen-sensing proline hydroxylase. organism: Human HIF-1 alpha substrate; purified recombinant hydroxylase tissue_or_cell_type: Cell-free experimental_model: Purified enzyme with human HIF-1 alpha-derived peptide substrate limitations: Peptide hydroxylation does not directly establish HIF degradation or transcription changes in intact cells; ankyrin probe is not physiological HIF. exposure: Ascorbate versus omission/alternative reducing agents; exact concentrations and enzyme constructs not recovered from primary abstract. cross_nutrient: true evidence_location: Primary abstract rate/extent and substrate comparisons [c-reg-flashman] Investigating the dependence of the hypoxia-inducible factor hydroxylases (factor inhibiting HIF and prolyl hydroxylase domain 2) on ascorbate and other reducing agents. (2010). https://pubmed.ncbi.nlm.nih.gov/20055761/ DOI: 10.1042/bj20091609
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.