{"id":"1fda96e9-bf4f-53c5-86f1-31ad7bb38ad6","stable_key":"4d8e4781-3878-5818-8d0a-7dbd6e024555:chromium-transferrin-conformation","predicate":"modulates","statement":"A human chromium-transferrin conformation formed 5–60 minutes after loading released chromium rapidly at endosomal pH, whereas the slowly formed conformation used in many older assays released it slowly.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"afba872e-61f4-5047-b13a-95c0c97e91bf","mechanism_event_label":"Different preparation states can explain different release-rate measurements without requiring one universal rate.","subject":{"id":"c6476f4d-d5f7-5a67-ae1f-661a7f3d8a14","slug":"human-chromium-loaded-transferrin","display_name":"Human chromium(III)-loaded transferrin","entity_type_key":"protein_state"},"object":{"id":"ee5123b3-4cd4-544f-bcde-25fddd9dae04","slug":"transferrin-chromium-release","display_name":"Chromium release from transferrin","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"afba872e-61f4-5047-b13a-95c0c97e91bf","stable_key":"4d8e4781-3878-5818-8d0a-7dbd6e024555:chromium-transferrin-conformation-event","event_type":"biochemical_relationship","label":"Different preparation states can explain different release-rate measurements without requiring one universal rate.","description":"A human chromium-transferrin conformation formed 5–60 minutes after loading released chromium rapidly at endosomal pH, whereas the slowly formed conformation used in many older assays released it slowly.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"c6476f4d-d5f7-5a67-ae1f-661a7f3d8a14","slug":"human-chromium-loaded-transferrin","display_name":"Human chromium(III)-loaded transferrin","entity_type_key":"protein_state"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"ee5123b3-4cd4-544f-bcde-25fddd9dae04","slug":"transferrin-chromium-release","display_name":"Chromium release from transferrin","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/chromium-research/32088595.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"6fd8562bf1ad589db2876f59b6ecd37beda818b8d349e5a42e50d00bb909de0a\", \"start_char\": 0, \"end_char\": 1535, \"text_sha256\": \"6fd8562bf1ad589db2876f59b6ecd37beda818b8d349e5a42e50d00bb909de0a\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Time-dependent spectroscopy and release kinetics","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Human apo-transferrin loaded at pH 7.4 in 25 mM bicarbonate; conformations followed over time","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Preparation time changes the protein-metal state. Kinetics alone do not establish essentiality, nutritional benefit or complete cellular delivery.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Chromium research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"chromium","display_name":"Chromium","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Human and bovine serum transferrin; human conformation series","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Different preparation states can explain different release-rate measurements without requiring one universal rate.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[chromium-p32088595] Significance of conformation changes during the binding and release of chromium(III) from human serum transferrin. (2020). https://pubmed.ncbi.nlm.nih.gov/32088595/ DOI: 10.1016/j.jinorgbio.2020.111040","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Endosome-mimicking in-vitro solution","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"77404dad-b5d7-5f87-a4e0-7a7bd336b9cc","evidence_kind":"source_excerpt","locator":"Lines 185-196","start_line":185,"end_line":196,"excerpt":"### chromium-transferrin-conformation\nA human chromium-transferrin conformation formed 5–60 minutes after loading released chromium rapidly at endosomal pH, whereas the slowly formed conformation used in many older assays released it slowly.\nCondition category: normal\nnutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Different preparation states can explain different release-rate measurements without requiring one universal rate.\norganism: Human and bovine serum transferrin; human conformation series\ntissue_or_cell_type: Endosome-mimicking in-vitro solution\nexperimental_model: Time-dependent spectroscopy and release kinetics\nlimitations: Preparation time changes the protein-metal state. Kinetics alone do not establish essentiality, nutritional benefit or complete cellular delivery.\nexposure: Human apo-transferrin loaded at pH 7.4 in 25 mM bicarbonate; conformations followed over time\nevidence_span: {\"source_cache\": \"artifacts/chromium-research/32088595.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"6fd8562bf1ad589db2876f59b6ecd37beda818b8d349e5a42e50d00bb909de0a\", \"start_char\": 0, \"end_char\": 1535, \"text_sha256\": \"6fd8562bf1ad589db2876f59b6ecd37beda818b8d349e5a42e50d00bb909de0a\"}\n[chromium-p32088595] Significance of conformation changes during the binding and release of chromium(III) from human serum transferrin. (2020). https://pubmed.ncbi.nlm.nih.gov/32088595/ DOI: 10.1016/j.jinorgbio.2020.111040","model_system":"Time-dependent spectroscopy and release kinetics","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [chromium-p32088595] Significance of conformation changes during the binding and release of chromium(III) from human serum transferrin. (2020). https://pubmed.ncbi.nlm.nih.gov/32088595/ DOI: 10.1016/j.jinorgbio.2020.111040","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"fa96342a-ca01-5425-98d9-d50e29bf0abd","stable_key":"import-4d8e4781-3878-5818-8d0a-7dbd6e024555","title":"Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (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":"6cae22f9104c6de041b25c23b0fd2884cc57707ac0c9a87c20b0e665d16de5ab","revision_id":"22893798-8329-5295-9c9d-82169032fc79","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}