{"id":"2ed85f48-0e7b-590f-b0a2-96e5d89eb8d2","stable_key":"27e0c1cf-7726-5164-8b15-27a631584cd0:choline-chpt1-pc","predicate":"synthesizes","statement":"Human CHPT1 catalyzes the PC-producing final step of the Kennedy pathway with choline-headgroup substrate selectivity.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"2f78df0c-0860-567f-ba4a-9dac66e8e87f","mechanism_event_label":"One terminal enzyme specializes in making phosphatidylcholine.","subject":{"id":"807551ce-9bf3-5afe-a9f4-85e19e181b33","slug":"chpt1","display_name":"Human choline phosphotransferase 1 / CHPT1","entity_type_key":"protein"},"object":{"id":"2f77ef6d-3ecd-5a80-9ca3-3cbea403d9fc","slug":"phosphatidylcholine","display_name":"Phosphatidylcholine","entity_type_key":"lipid"},"evidence_count":1,"mechanism_event":{"id":"2f78df0c-0860-567f-ba4a-9dac66e8e87f","stable_key":"27e0c1cf-7726-5164-8b15-27a631584cd0:choline-chpt1-pc-event","event_type":"biochemical_relationship","label":"One terminal enzyme specializes in making phosphatidylcholine.","description":"Human CHPT1 catalyzes the PC-producing final step of the Kennedy pathway with choline-headgroup substrate selectivity.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"e1f22bfd-771d-5405-b2d4-ff5f4ae4d95f","slug":"cdp-choline","display_name":"CDP-choline","entity_type_key":"small_molecule"},"role":"activated_headgroup","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"13ba4537-bd0f-5817-9aae-aa255edcb5d6","slug":"diacylglycerol","display_name":"DAG","entity_type_key":"lipid"},"role":"lipid_substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"807551ce-9bf3-5afe-a9f4-85e19e181b33","slug":"chpt1","display_name":"Human choline phosphotransferase 1 / CHPT1","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"2f77ef6d-3ecd-5a80-9ca3-3cbea403d9fc","slug":"phosphatidylcholine","display_name":"Phosphatidylcholine","entity_type_key":"lipid"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/choline-research/40435706.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"d08b2ce68e8731e88e1204dc1b09d1301020452752a630a880ec3a2cdb0f2351\", \"start_char\": 0, \"end_char\": 1339, \"text_sha256\": \"d08b2ce68e8731e88e1204dc1b09d1301020452752a630a880ec3a2cdb0f2351\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human CHPT1 cryo-EM, sequence analysis and biochemical characterization","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"CDP-choline/CDP-ethanolamine substrate selectivity","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Human CHPT1 and CEPT1 remain separate. Evolutionary suggestions about oviparous species are not asserted as human bifunctionality.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Choline research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"choline","display_name":"Choline","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Human proteins; evolutionary comparisons explicitly separate","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"One terminal enzyme specializes in making phosphatidylcholine.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[choline-p40435706] Structural basis for substrate selectivity and evolutionary insights into human choline phosphotransferase 1. (2025). https://pubmed.ncbi.nlm.nih.gov/40435706/ DOI: 10.1016/j.bbrc.2025.152082","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Membrane phospholipid synthesis","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"f6b35702-6c07-57a0-b2f1-3c35f839e2b2","evidence_kind":"source_excerpt","locator":"Lines 763-774","start_line":763,"end_line":774,"excerpt":"### choline-chpt1-pc\nHuman CHPT1 catalyzes the PC-producing final step of the Kennedy pathway with choline-headgroup substrate selectivity.\nCondition category: normal\nnutrient_topic: Choline research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: One terminal enzyme specializes in making phosphatidylcholine.\norganism: Human proteins; evolutionary comparisons explicitly separate\ntissue_or_cell_type: Membrane phospholipid synthesis\nexperimental_model: Human CHPT1 cryo-EM, sequence analysis and biochemical characterization\nlimitations: Human CHPT1 and CEPT1 remain separate. Evolutionary suggestions about oviparous species are not asserted as human bifunctionality.\nexposure: CDP-choline/CDP-ethanolamine substrate selectivity\nevidence_span: {\"source_cache\": \"artifacts/choline-research/40435706.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"d08b2ce68e8731e88e1204dc1b09d1301020452752a630a880ec3a2cdb0f2351\", \"start_char\": 0, \"end_char\": 1339, \"text_sha256\": \"d08b2ce68e8731e88e1204dc1b09d1301020452752a630a880ec3a2cdb0f2351\"}\n[choline-p40435706] Structural basis for substrate selectivity and evolutionary insights into human choline phosphotransferase 1. 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