{"id":"2e1c4cb1-e9f4-5a18-9a90-a7b1be910be1","stable_key":"ec174d5a-4903-5745-8646-df0e9d4265e8:mthfd1l-short-no-dehydrogenase","predicate":"lacks-detectable-activity-toward","statement":"The purified short human MTHFD1L isoform lacked detectable methylene-THF dehydrogenase activity.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"41d12b20-5578-52e3-9be6-9301d5078db8","mechanism_event_label":"This short isoform cannot be assumed to replace MTHFD2.","subject":{"id":"bf67b29c-edab-53f2-8d13-2f448690242d","slug":"human-mthfd1l-short-isoform","display_name":"Human MTHFD1L short isoform","entity_type_key":"protein"},"object":{"id":"0413b195-325e-5757-a72b-f445d65c17bc","slug":"5-10-methylenetetrahydrofolate","display_name":"5,10-Methylenetetrahydrofolate","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"41d12b20-5578-52e3-9be6-9301d5078db8","stable_key":"ec174d5a-4903-5745-8646-df0e9d4265e8:mthfd1l-short-no-dehydrogenase-event","event_type":"biochemical_relationship","label":"This short isoform cannot be assumed to replace MTHFD2.","description":"The purified short human MTHFD1L isoform lacked detectable methylene-THF dehydrogenase activity.","status":"provisional","compartment":{"slug":"mitochondrial-matrix","display_name":"Mitochondrial matrix"},"participants":[{"entity":{"id":"bf67b29c-edab-53f2-8d13-2f448690242d","slug":"human-mthfd1l-short-isoform","display_name":"Human MTHFD1L short isoform","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"0413b195-325e-5757-a72b-f445d65c17bc","slug":"5-10-methylenetetrahydrofolate","display_name":"5,10-Methylenetetrahydrofolate","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"experimental_model","value_text":"Purified short isoform","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Assay conditions described in the linked primary study.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Negative activity result is assay-specific; full-length MTHFD1L has synthetase activity.","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":"This short isoform cannot be assumed to replace MTHFD2.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[prasannan-2009] Human mitochondrial C1-tetrahydrofolate synthase: submitochondrial localization of the full-length enzyme and characterization of a short isoform (2009). https://pubmed.ncbi.nlm.nih.gov/18996079/ DOI: 10.1016/j.abb.2008.10.028","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":"75cdd657-ebbd-56a5-bd29-7709df75599d","evidence_kind":"source_excerpt","locator":"Lines 887-897","start_line":887,"end_line":897,"excerpt":"### mthfd1l-short-no-dehydrogenase\nThe purified short human MTHFD1L isoform lacked detectable methylene-THF dehydrogenase activity.\nCondition category: normal\nnutrient_topic: Folate and folic acid research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: This short isoform cannot be assumed to replace MTHFD2.\norganism: Homo sapiens\ntissue_or_cell_type: Cell-free\nexperimental_model: Purified short isoform\nlimitations: Negative activity result is assay-specific; full-length MTHFD1L has synthetase activity.\nexposure: Assay conditions described in the linked primary study.\n[prasannan-2009] Human mitochondrial C1-tetrahydrofolate synthase: submitochondrial localization of the full-length enzyme and characterization of a short isoform (2009). https://pubmed.ncbi.nlm.nih.gov/18996079/ DOI: 10.1016/j.abb.2008.10.028","model_system":"Purified short isoform","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [prasannan-2009] Human mitochondrial C1-tetrahydrofolate synthase: submitochondrial localization of the full-length enzyme and characterization of a short isoform (2009). https://pubmed.ncbi.nlm.nih.gov/18996079/ DOI: 10.1016/j.abb.2008.10.028","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}