{"id":"2327bbf1-642d-58d6-8821-4e778915b752","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:phospho1-phosphocholine-hydrolysis","predicate":"hydrolyzed_to","statement":"Human PHOSPHO1 also hydrolyzes phosphocholine, producing inorganic phosphate and choline.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"9dd5da13-211f-578d-a327-8f5aece0df7f","mechanism_event_label":"A second phospholipid-headgroup metabolite can supply phosphate.","subject":{"id":"2159176b-2e94-5403-98e9-97e966b38b81","slug":"phosphocholine","display_name":"Phosphocholine","entity_type_key":"small_molecule"},"object":{"id":"ee63fe8e-92f3-552f-8049-a5f1fa1e1523","slug":"phosphate-ion","display_name":"Inorganic phosphate (Pi; protonation depends on pH)","entity_type_key":"ion"},"evidence_count":1,"mechanism_event":{"id":"9dd5da13-211f-578d-a327-8f5aece0df7f","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:phospho1-phosphocholine-hydrolysis-event","event_type":"biochemical_relationship","label":"A second phospholipid-headgroup metabolite can supply phosphate.","description":"Human PHOSPHO1 also hydrolyzes phosphocholine, producing inorganic phosphate and choline.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"bb7ed19e-2f65-5951-8963-40d6b3249b71","slug":"phospho1","display_name":"Phosphoethanolamine/phosphocholine phosphatase PHOSPHO1","entity_type_key":"protein"},"role":"catalyst","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"2159176b-2e94-5403-98e9-97e966b38b81","slug":"phosphocholine","display_name":"Phosphocholine","entity_type_key":"small_molecule"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"d31225b7-8e94-5857-9ea1-67ac794b1f15","slug":"water","display_name":"H2O","entity_type_key":"small_molecule"},"role":"hydrolysis_cosubstrate","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"role":"enzyme_cofactor","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"ee63fe8e-92f3-552f-8049-a5f1fa1e1523","slug":"phosphate-ion","display_name":"Inorganic phosphate (Pi; protonation depends on pH)","entity_type_key":"ion"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"8e1d19fd-ad66-575d-81c4-9122f78915e5","slug":"choline","display_name":"Choline","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"experimental_model","value_text":"Purified-enzyme substrate assay","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This reaction uses magnesium-dependent machinery; calcium is the eventual mineral constituent, not the demonstrated phosphatase cofactor.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Calcium research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"calcium","display_name":"Calcium","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"A second phospholipid-headgroup metabolite can supply phosphate.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[roberts2004] Human PHOSPHO1 exhibits high specific phosphoethanolamine and phosphocholine phosphatase activities (2004). https://pubmed.ncbi.nlm.nih.gov/15175005/ DOI: 10.1042/BJ20040511","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Recombinant enzyme","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"06ae760e-d497-5e38-a00a-09396199857d","evidence_kind":"source_excerpt","locator":"Lines 908-917","start_line":908,"end_line":917,"excerpt":"### phospho1-phosphocholine-hydrolysis\nHuman PHOSPHO1 also hydrolyzes phosphocholine, producing inorganic phosphate and choline.\nCondition category: normal\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A second phospholipid-headgroup metabolite can supply phosphate.\norganism: Homo sapiens\ntissue_or_cell_type: Recombinant enzyme\nexperimental_model: Purified-enzyme substrate assay\nlimitations: This reaction uses magnesium-dependent machinery; calcium is the eventual mineral constituent, not the demonstrated phosphatase cofactor.\n[roberts2004] Human PHOSPHO1 exhibits high specific phosphoethanolamine and phosphocholine phosphatase activities (2004). https://pubmed.ncbi.nlm.nih.gov/15175005/ DOI: 10.1042/BJ20040511","model_system":"Purified-enzyme substrate assay","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [roberts2004] Human PHOSPHO1 exhibits high specific phosphoethanolamine and phosphocholine phosphatase activities (2004). https://pubmed.ncbi.nlm.nih.gov/15175005/ DOI: 10.1042/BJ20040511","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"3c083fa0-59c6-50e9-af42-678d0e3c1006","stable_key":"import-434e1e27-eb90-583a-956b-62472726ffba","title":"Calcium: mechanism-first literature curation (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":"965c934d6b147f2b62f8d45ce6d7a87681a600bfe5c46a585b4704889afd3fc1","revision_id":"543ec48b-4f70-5197-9d76-f5a3c443664c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}