{"id":"b573cfee-1190-5770-96d5-3ab55b00646a","stable_key":"0ad8610d-d575-5870-b7cd-763a9f750783:copper-heph-transferrin-loading","predicate":"promotes_formation_of","statement":"Human hephaestin catalyzed diferric transferrin formation from Fe(II) and apotransferrin in vitro.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"5b625d47-6cd9-53ce-be78-eac8631df343","mechanism_event_label":"Copper-dependent iron processing helps load iron onto its blood carrier.","subject":{"id":"a89b5f9c-0a58-5ef6-8e27-b2a8747b26a0","slug":"heph","display_name":"Human hephaestin / HEPH","entity_type_key":"protein"},"object":{"id":"50bd872a-478e-507f-80fa-bb66274d7b0c","slug":"diferric-transferrin","display_name":"Human transferrin loaded with two ferric ions","entity_type_key":"protein_state"},"evidence_count":1,"mechanism_event":{"id":"5b625d47-6cd9-53ce-be78-eac8631df343","stable_key":"0ad8610d-d575-5870-b7cd-763a9f750783:copper-heph-transferrin-loading-event","event_type":"biochemical_relationship","label":"Copper-dependent iron processing helps load iron onto its blood carrier.","description":"Human hephaestin catalyzed diferric transferrin formation from Fe(II) and apotransferrin in vitro.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"59d6d1cd-df32-5b58-b950-3188bc7b95d6","slug":"iron-ii","display_name":"Ferrous iron","entity_type_key":"ion"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"964be7ac-43bd-5f3e-8326-94f0590de67a","slug":"iron-iii","display_name":"Ferric iron","entity_type_key":"ion"},"role":"transferrin-bound product","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"a89b5f9c-0a58-5ef6-8e27-b2a8747b26a0","slug":"heph","display_name":"Human hephaestin / HEPH","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"50bd872a-478e-507f-80fa-bb66274d7b0c","slug":"diferric-transferrin","display_name":"Human transferrin loaded with two ferric ions","entity_type_key":"protein_state"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/copper-research/16274220.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"7f88de566cf98e9aad1df97f91b7b37a4d8e685b842c164db25a196b09c0b976\", \"start_char\": 0, \"end_char\": 1880, \"text_sha256\": \"7f88de566cf98e9aad1df97f91b7b37a4d8e685b842c164db25a196b09c0b976\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified recombinant human hephaestin","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Fe(II) substrate and apotransferrin assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Soluble recombinant construct; average measured copper loading of 3.13 atoms is not a universal mature-protein stoichiometry.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Copper research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"copper","display_name":"Copper","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Human protein produced in baby hamster kidney cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Copper-dependent iron processing helps load iron onto its blood carrier.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[copper-p16274220] Recombinant expression and functional characterization of human hephaestin: a multicopper oxidase with ferroxidase activity. (2005). https://pubmed.ncbi.nlm.nih.gov/16274220/ DOI: 10.1021/bi051559k","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified soluble hephaestin construct","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"c172258a-c407-57ea-9c9e-bce8ab9a830d","evidence_kind":"source_excerpt","locator":"Lines 780-791","start_line":780,"end_line":791,"excerpt":"### copper-heph-transferrin-loading\nHuman hephaestin catalyzed diferric transferrin formation from Fe(II) and apotransferrin in vitro.\nCondition category: normal\nnutrient_topic: Copper research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Copper-dependent iron processing helps load iron onto its blood carrier.\norganism: Human protein produced in baby hamster kidney cells\ntissue_or_cell_type: Purified soluble hephaestin construct\nexperimental_model: Purified recombinant human hephaestin\nlimitations: Soluble recombinant construct; average measured copper loading of 3.13 atoms is not a universal mature-protein stoichiometry.\nexposure: Fe(II) substrate and apotransferrin assays\nevidence_span: {\"source_cache\": \"artifacts/copper-research/16274220.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"7f88de566cf98e9aad1df97f91b7b37a4d8e685b842c164db25a196b09c0b976\", \"start_char\": 0, \"end_char\": 1880, \"text_sha256\": \"7f88de566cf98e9aad1df97f91b7b37a4d8e685b842c164db25a196b09c0b976\"}\n[copper-p16274220] Recombinant expression and functional characterization of human hephaestin: a multicopper oxidase with ferroxidase activity. 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