{"id":"dba9cb8c-7dc0-5db3-94d1-dc6a5b67ed1d","stable_key":"ec174d5a-4903-5745-8646-df0e9d4265e8:folate-fpgs-thf-substrate","predicate":"polyglutamylates","statement":"Purified human cytosolic FPGS used tetrahydrofolate as an effective substrate for polyglutamate synthesis.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"20a4a335-9ad3-5b4d-ae1d-5871324b7e3e","mechanism_event_label":"FPGS adds tails that help retain usable folate.","subject":{"id":"ef23c0b4-93bc-5f74-9889-cb7e573568a6","slug":"fpgs-cytosolic","display_name":"Human cytosolic FPGS isoform","entity_type_key":"protein"},"object":{"id":"d2b23343-c688-5fc3-9f42-bfac0050552b","slug":"tetrahydrofolate","display_name":"Tetrahydrofolate","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"20a4a335-9ad3-5b4d-ae1d-5871324b7e3e","stable_key":"ec174d5a-4903-5745-8646-df0e9d4265e8:folate-fpgs-thf-substrate-event","event_type":"biochemical_relationship","label":"FPGS adds tails that help retain usable folate.","description":"Purified human cytosolic FPGS used tetrahydrofolate as an effective substrate for polyglutamate synthesis.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"ef23c0b4-93bc-5f74-9889-cb7e573568a6","slug":"fpgs-cytosolic","display_name":"Human cytosolic FPGS isoform","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"d2b23343-c688-5fc3-9f42-bfac0050552b","slug":"tetrahydrofolate","display_name":"Tetrahydrofolate","entity_type_key":"small_molecule"},"role":"object","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"7da684a4-2641-5bc6-93ae-8c6aa384e487","slug":"glutamate","display_name":"L-Glutamate","entity_type_key":"small_molecule"},"role":"added substrate","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"81c45abb-713d-521f-9854-23288f880831","slug":"folate-polyglutamates","display_name":"Folate polyglutamates","entity_type_key":"chemical_species"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"experimental_model","value_text":"Purified human cytosolic FPGS expressed in bacteria","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Comparative substrate enzyme assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Purified substrate preference does not quantify intact-cell flux.","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 protein expressed in Escherichia coli","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"FPGS adds tails that help retain usable folate.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[chen1996] Purification and properties of human cytosolic folylpoly-gamma-glutamate synthetase and organization, localization, and differential splicing of its gene (1996). https://pubmed.ncbi.nlm.nih.gov/8662720/ DOI: 10.1074/jbc.271.22.13077","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified enzyme","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"eacac5e7-4107-5c6d-9957-177648ba2ea8","evidence_kind":"source_excerpt","locator":"Lines 255-265","start_line":255,"end_line":265,"excerpt":"### folate-fpgs-thf-substrate\nPurified human cytosolic FPGS used tetrahydrofolate as an effective substrate for polyglutamate synthesis.\nCondition category: normal\nnutrient_topic: Folate and folic acid research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: FPGS adds tails that help retain usable folate.\norganism: Homo sapiens protein expressed in Escherichia coli\ntissue_or_cell_type: Purified enzyme\nexperimental_model: Purified human cytosolic FPGS expressed in bacteria\nlimitations: Purified substrate preference does not quantify intact-cell flux.\nexposure: Comparative substrate enzyme assays\n[chen1996] Purification and properties of human cytosolic folylpoly-gamma-glutamate synthetase and organization, localization, and differential splicing of its gene (1996). https://pubmed.ncbi.nlm.nih.gov/8662720/ DOI: 10.1074/jbc.271.22.13077","model_system":"Purified human cytosolic FPGS expressed in bacteria","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [chen1996] Purification and properties of human cytosolic folylpoly-gamma-glutamate synthetase and organization, localization, and differential splicing of its gene (1996). https://pubmed.ncbi.nlm.nih.gov/8662720/ DOI: 10.1074/jbc.271.22.13077","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}