{"id":"63a35c9e-331c-5434-a67f-d5da5da37fe7","stable_key":"ec174d5a-4903-5745-8646-df0e9d4265e8:folate-dhfr-dhf-recycling","predicate":"reduces","statement":"Human liver DHFR converted 7,8-dihydrofolate to tetrahydrofolate in NADPH-containing assays.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"a2dcc491-1cfd-5b18-8c29-ba1cc21670de","mechanism_event_label":"DHFR regenerates reduced folate from DHF.","subject":{"id":"3e8c5745-4f15-5fde-865e-82529344a044","slug":"dhfr","display_name":"Human dihydrofolate reductase / DHFR","entity_type_key":"protein"},"object":{"id":"b6feb26d-6f4d-5232-b54a-650e125fcdf8","slug":"dihydrofolate","display_name":"7,8-Dihydrofolate","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"a2dcc491-1cfd-5b18-8c29-ba1cc21670de","stable_key":"ec174d5a-4903-5745-8646-df0e9d4265e8:folate-dhfr-dhf-recycling-event","event_type":"biochemical_relationship","label":"DHFR regenerates reduced folate from DHF.","description":"Human liver DHFR converted 7,8-dihydrofolate to tetrahydrofolate in NADPH-containing assays.","status":"provisional","compartment":{"slug":"cytosol","display_name":"Cytosol"},"participants":[{"entity":{"id":"3e8c5745-4f15-5fde-865e-82529344a044","slug":"dhfr","display_name":"Human dihydrofolate reductase / DHFR","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"b6feb26d-6f4d-5232-b54a-650e125fcdf8","slug":"dihydrofolate","display_name":"7,8-Dihydrofolate","entity_type_key":"small_molecule"},"role":"object","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"d2b23343-c688-5fc3-9f42-bfac0050552b","slug":"tetrahydrofolate","display_name":"Tetrahydrofolate","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"4aba2a5e-8d06-5304-bb01-c0402b225a94","slug":"nadph","display_name":"NADPH","entity_type_key":"small_molecule"},"role":"reducing cofactor","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"experimental_model","value_text":"Fresh human liver extracts from six donors and rat comparison","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"DHF substrate; THF quantified by HPLC","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Assay chemistry, not an outcome study.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Folate and folic acid research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"folate","display_name":"Folate (vitamin B9)","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"DHFR regenerates reduced folate from DHF.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[bailey2009] The extremely slow and variable activity of dihydrofolate reductase in human liver and its implications for high folic acid intake (2009). https://pubmed.ncbi.nlm.nih.gov/19706381/ DOI: 10.1073/pnas.0902072106","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Liver extracts","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"7479df66-dfb2-5ac2-9d96-7e82e5535692","evidence_kind":"source_excerpt","locator":"Lines 363-373","start_line":363,"end_line":373,"excerpt":"### folate-dhfr-dhf-recycling\nHuman liver DHFR converted 7,8-dihydrofolate to tetrahydrofolate in NADPH-containing assays.\nCondition category: normal\nnutrient_topic: Folate and folic acid research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: DHFR regenerates reduced folate from DHF.\norganism: Homo sapiens\ntissue_or_cell_type: Liver extracts\nexperimental_model: Fresh human liver extracts from six donors and rat comparison\nlimitations: Assay chemistry, not an outcome study.\nexposure: DHF substrate; THF quantified by HPLC\n[bailey2009] The extremely slow and variable activity of dihydrofolate reductase in human liver and its implications for high folic acid intake (2009). https://pubmed.ncbi.nlm.nih.gov/19706381/ DOI: 10.1073/pnas.0902072106","model_system":"Fresh human liver extracts from six donors and rat comparison","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [bailey2009] The extremely slow and variable activity of dihydrofolate reductase in human liver and its implications for high folic acid intake (2009). https://pubmed.ncbi.nlm.nih.gov/19706381/ DOI: 10.1073/pnas.0902072106","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"f4ce1a62-9582-5f7a-84f5-a23d0e1bfc68","stable_key":"import-ec174d5a-4903-5745-8646-df0e9d4265e8","title":"Folate and folic acid: mechanisms, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"e564d43989ece1006c95cd0748e9af6fe369074599a2eebba0a99ebff864b0dd","revision_id":"76674a33-b2a1-5e41-b71b-44399038ff7c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}