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(2010). https://pubmed.ncbi.nlm.nih.gov/20055761/ DOI: 10.1042/bj20091609","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cell-free","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"bff59b86-f581-5685-b3f4-f3051421967f","evidence_kind":"source_excerpt","locator":"Lines 1117-1129","start_line":1117,"end_line":1129,"excerpt":"### c-reg-phd2-ascorbate\nAscorbate increased the initial rate and extent of PHD2-catalyzed hydroxylation at both tested human HIF-1 alpha prolyl sites in purified-enzyme peptide experiments.\nCondition category: normal\nnutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Vitamin C increased the activity of an isolated oxygen-sensing proline hydroxylase.\norganism: Human HIF-1 alpha substrate; purified recombinant hydroxylase\ntissue_or_cell_type: Cell-free\nexperimental_model: Purified enzyme with human HIF-1 alpha-derived peptide substrate\nlimitations: Peptide hydroxylation does not directly establish HIF degradation or transcription changes in intact cells; ankyrin probe is not physiological HIF.\nexposure: Ascorbate versus omission/alternative reducing agents; exact concentrations and enzyme constructs not recovered from primary abstract.\ncross_nutrient: true\nevidence_location: Primary abstract rate/extent and substrate comparisons\n[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. 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