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(2004). https://pubmed.ncbi.nlm.nih.gov/15465040/ DOI: 10.1016/j.bbrc.2004.09.073","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"microsomal enzyme preparation","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"d5944be4-b803-5a9f-90d3-a4308b74c157","evidence_kind":"source_excerpt","locator":"Lines 302-315","start_line":302,"end_line":315,"excerpt":"### vd-act-cyp2r1-d2\nRecombinant human CYP2R1 hydroxylated ergocalciferol at C25 to form 25-hydroxyvitamin D2.\nCondition category: normal\nnutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The same first-step enzyme also activates D2.\norganism: Homo sapiens protein\ntissue_or_cell_type: microsomal enzyme preparation\nexperimental_model: Recombinant human enzyme product identification\nlimitations: A shared enzyme does not by itself prove equal long-term serum responses to all D2 and D3 dosing regimens.\nexposure: D2 substrate incubations; detailed concentration/time not available in abstract.\ncross_nutrient: false\nevidence_location: Primary abstract, substrate product positions and kinetic comparison.\nnutrient: Vitamin D2 and D3\n[shinkyo2004] Metabolism of vitamin D by human microsomal CYP2R1. 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