{"id":"6e53c51a-f2b2-5a52-af24-344f42436a97","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-abs-food-acid","predicate":"promotes","statement":"In the egg-yolk/human saliva model, acidification to pH 1.5 permitted limited cobalamin transfer to R binder; virtually none occurred above pH 2 despite pepsin.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"c6ebce38-2ebe-5e08-aebc-26ccdcaf067a","mechanism_event_label":"Acid enabled release and capture of B12 from this food model.","subject":{"id":"16a9848a-023b-5828-9fd1-e28b9eadb901","slug":"hydrogen-ion","display_name":"Hydrogen ion","entity_type_key":"ion"},"object":{"id":"d3e9d853-4cf8-5a5b-a7ee-336e333d0ab3","slug":"egg-yolk-cobalamin-transfer","display_name":"Egg-yolk cobalamin transfer to human haptocorrin","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"c6ebce38-2ebe-5e08-aebc-26ccdcaf067a","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-abs-food-acid-event","event_type":"biochemical_relationship","label":"Acid enabled release and capture of B12 from this food model.","description":"In the egg-yolk/human saliva model, acidification to pH 1.5 permitted limited cobalamin transfer to R binder; virtually none occurred above pH 2 despite pepsin.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"b6d9b937-895d-5e0a-8cc5-0454a0b7d373","slug":"vitamin-b12","display_name":"Vitamin B12 (cobalamins)","entity_type_key":"chemical_species"},"role":"nutrient","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"21f01bdf-1da9-59c3-af35-c67281e89dd4","slug":"tcn1","display_name":"Human haptocorrin / TCN1","entity_type_key":"protein"},"role":"acceptor","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"16a9848a-023b-5828-9fd1-e28b9eadb901","slug":"hydrogen-ion","display_name":"Hydrogen ion","entity_type_key":"ion"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"d3e9d853-4cf8-5a5b-a7ee-336e333d0ab3","slug":"egg-yolk-cobalamin-transfer","display_name":"Egg-yolk cobalamin transfer to human haptocorrin","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"false","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"In vitro egg-yolk cobalamin-binding protein mixed with human saliva/gastric juice","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"In vitro pH manipulation","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Food-specific biochemical model; this pH threshold is not a clinical blood threshold or proof that all foods behave identically. Pepsin preparation species was not specified in the inspected abstract.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-b12","display_name":"Vitamin B12 (cobalamins)","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Acid enabled release and capture of B12 from this food model.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[carmel-1990-food-transfer] Transfer of cobalamin from the cobalamin-binding protein of egg yolk to R binder of human saliva and gastric juice. (1990). https://pubmed.ncbi.nlm.nih.gov/2110915/ DOI: 10.1016/0016-5085(90)91076-i","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Gastric luminal digestion model","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"dd11190a-6e99-5b6a-9086-f39c1d4c49ee","evidence_kind":"source_excerpt","locator":"Lines 88-99","start_line":88,"end_line":99,"excerpt":"### b12-abs-food-acid\nIn the egg-yolk/human saliva model, acidification to pH 1.5 permitted limited cobalamin transfer to R binder; virtually none occurred above pH 2 despite pepsin.\nCondition category: normal\nnutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Acid enabled release and capture of B12 from this food model.\norganism: Homo sapiens\ntissue_or_cell_type: Gastric luminal digestion model\nexperimental_model: In vitro egg-yolk cobalamin-binding protein mixed with human saliva/gastric juice\nlimitations: Food-specific biochemical model; this pH threshold is not a clinical blood threshold or proof that all foods behave identically. Pepsin preparation species was not specified in the inspected abstract.\nexposure: In vitro pH manipulation\ncross_nutrient: false\n[carmel-1990-food-transfer] Transfer of cobalamin from the cobalamin-binding protein of egg yolk to R binder of human saliva and gastric juice. (1990). https://pubmed.ncbi.nlm.nih.gov/2110915/ DOI: 10.1016/0016-5085(90)91076-i","model_system":"In vitro egg-yolk cobalamin-binding protein mixed with human saliva/gastric juice","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [carmel-1990-food-transfer] Transfer of cobalamin from the cobalamin-binding protein of egg yolk to R binder of human saliva and gastric juice. (1990). https://pubmed.ncbi.nlm.nih.gov/2110915/ DOI: 10.1016/0016-5085(90)91076-i","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"73145023-2982-5848-aff2-8d8875d6b9c5","stable_key":"import-7fc92b9e-9cbf-556e-8719-6b5244625250","title":"Vitamin B12: 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":"ad5b3a51d36e856aa7fdfd1cc23f690b094689bad87d28e1a621a54675a01c92","revision_id":"118bd616-0c13-549f-bfeb-bc439715b89c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}