{"id":"deb1a9ee-3f87-5b74-94eb-b42c94f6996a","stable_key":"4fef8d72-f107-5eb5-b2fb-483ca85465e0:k2-membrane-bovine-proc","predicate":"binds_calcium_dependently_to","statement":"The tested bovine-proc Gla-domain protein showed calcium-specific contact with negatively charged phospholipid monolayers.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"efd6ad89-e5a2-54a1-8717-c3492241d599","mechanism_event_label":"Carboxylation supports a protein surface that interacts with calcium and membranes.","subject":{"id":"92ac57fc-cdb3-55ca-b9c0-829cc20242e1","slug":"bovine-proc","display_name":"Bovine protein C / PROC","entity_type_key":"protein"},"object":{"id":"0e2dd859-6135-556e-938f-d177f1e8c1ad","slug":"phosphatidylserine","display_name":"Phosphatidylserine","entity_type_key":"lipid"},"evidence_count":1,"mechanism_event":{"id":"efd6ad89-e5a2-54a1-8717-c3492241d599","stable_key":"4fef8d72-f107-5eb5-b2fb-483ca85465e0:k2-membrane-bovine-proc-event","event_type":"biochemical_relationship","label":"Carboxylation supports a protein surface that interacts with calcium and membranes.","description":"The tested bovine-proc Gla-domain protein showed calcium-specific contact with negatively charged phospholipid monolayers.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"e359bc15-e675-5d83-b0fe-1d70814e130b","slug":"calcium-ion","display_name":"Calcium ion","entity_type_key":"ion"},"role":"required_assay_ion","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"92ac57fc-cdb3-55ca-b9c0-829cc20242e1","slug":"bovine-proc","display_name":"Bovine protein C / PROC","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"0e2dd859-6135-556e-938f-d177f1e8c1ad","slug":"phosphatidylserine","display_name":"Phosphatidylserine","entity_type_key":"lipid"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/k2-research/9609692.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"d29ed548c28e5a8015742351c50aa94c8853d0f1846794964b67a73324c879bd\", \"start_char\": 0, \"end_char\": 2064, \"text_sha256\": \"d29ed548c28e5a8015742351c50aa94c8853d0f1846794964b67a73324c879bd\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Protein adsorption to model phospholipid monolayers","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Phosphatidylserine-containing monolayers","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Model membrane binding, not whole-blood thrombosis. Species remain distinct.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin K2 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"k2","display_name":"Vitamin K2 / menaquinone family","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Purified human and bovine proteins","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Carboxylation supports a protein surface that interacts with calcium and membranes.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[k2-p9609692] Adsorption of vitamin K-dependent blood coagulation proteins to spread phospholipid monolayers as determined from combined measurements of the surface pressure and surface protein concentration. (1998). https://pubmed.ncbi.nlm.nih.gov/9609692/ DOI: 10.1021/bi973118+","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Calcium-dependent Gla-domain membrane contact","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"4e5d0221-681c-551a-a449-5ffe27f2d4d7","evidence_kind":"source_excerpt","locator":"Lines 981-992","start_line":981,"end_line":992,"excerpt":"### k2-membrane-bovine-proc\nThe tested bovine-proc Gla-domain protein showed calcium-specific contact with negatively charged phospholipid monolayers.\nCondition category: normal\nnutrient_topic: Vitamin K2 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Carboxylation supports a protein surface that interacts with calcium and membranes.\norganism: Purified human and bovine proteins\ntissue_or_cell_type: Calcium-dependent Gla-domain membrane contact\nexperimental_model: Protein adsorption to model phospholipid monolayers\nlimitations: Model membrane binding, not whole-blood thrombosis. Species remain distinct.\nexposure: Phosphatidylserine-containing monolayers\nevidence_span: {\"source_cache\": \"artifacts/k2-research/9609692.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"d29ed548c28e5a8015742351c50aa94c8853d0f1846794964b67a73324c879bd\", \"start_char\": 0, \"end_char\": 2064, \"text_sha256\": \"d29ed548c28e5a8015742351c50aa94c8853d0f1846794964b67a73324c879bd\"}\n[k2-p9609692] Adsorption of vitamin K-dependent blood coagulation proteins to spread phospholipid monolayers as determined from combined measurements of the surface pressure and surface protein concentration. (1998). https://pubmed.ncbi.nlm.nih.gov/9609692/ DOI: 10.1021/bi973118+","model_system":"Protein adsorption to model phospholipid monolayers","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [k2-p9609692] Adsorption of vitamin K-dependent blood coagulation proteins to spread phospholipid monolayers as determined from combined measurements of the surface pressure and surface protein concentration. (1998). https://pubmed.ncbi.nlm.nih.gov/9609692/ DOI: 10.1021/bi973118+","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"dfeae572-af3d-5042-a10e-e67596f9ab28","stable_key":"import-4fef8d72-f107-5eb5-b2fb-483ca85465e0","title":"Vitamin K2: menaquinone forms, carboxylation, recycling 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. 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