{"id":"91dc5e47-7d79-5db4-b8f4-59f142cfd389","stable_key":"4d8e4781-3878-5818-8d0a-7dbd6e024555:chromium-chromodulin-isolation-artifact","predicate":"after_cell_lysis_generates","statement":"Most Cr(III) formed in Cr(VI)-treated cells was associated with high-molecular-mass ligands; cell lysis redistributed chromium into a low-molecular-weight fraction spectroscopically similar to reported chromodulin.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"2de02e7e-c240-5198-be4c-a7f387b41b9c","mechanism_event_label":"Some apparent chromodulin-like material formed during sample preparation, raising doubts about its identity as a pre-existing cellular signal.","subject":{"id":"15b3e015-2780-5848-a962-64c9f67e8087","slug":"chromate","display_name":"Chromate / chromium(VI) oxyanion","entity_type_key":"ion"},"object":{"id":"4710de02-231f-59c2-ba49-0e6f0f44c7c3","slug":"low-molecular-weight-chromium-fraction","display_name":"Low-molecular-weight cellular chromium fraction","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"2de02e7e-c240-5198-be4c-a7f387b41b9c","stable_key":"4d8e4781-3878-5818-8d0a-7dbd6e024555:chromium-chromodulin-isolation-artifact-event","event_type":"biochemical_relationship","label":"Some apparent chromodulin-like material formed during sample preparation, raising doubts about its identity as a pre-existing cellular signal.","description":"Most Cr(III) formed in Cr(VI)-treated cells was associated with high-molecular-mass ligands; cell lysis redistributed chromium into a low-molecular-weight fraction spectroscopically similar to reported chromodulin.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"2d160bdf-c463-5f93-9e50-137f41a1f369","slug":"chromium-iii","display_name":"Trivalent chromium / Cr(III)","entity_type_key":"ion"},"role":"reduced_metal","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"15b3e015-2780-5848-a962-64c9f67e8087","slug":"chromate","display_name":"Chromate / chromium(VI) oxyanion","entity_type_key":"ion"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"4710de02-231f-59c2-ba49-0e6f0f44c7c3","slug":"low-molecular-weight-chromium-fraction","display_name":"Low-molecular-weight cellular chromium fraction","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/chromium-research/17263387.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"912905b2fefe0745017faae62124fe077d3944cde635ae1012ff76fc33094b35\", \"start_char\": 0, \"end_char\": 1638, \"text_sha256\": \"912905b2fefe0745017faae62124fe077d3944cde635ae1012ff76fc33094b35\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"X-ray absorption and EPR before and after cell fractionation","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Cr(VI)-treated cells; comparisons with model Cr(III) complexes","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"The artifact evidence concerns chromium(VI)-exposed cells and the tested isolation procedures. It does not negate the activity measured when an isolated peptide preparation is added to an enzyme assay.","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 A549/HepG2, hamster V79 and mouse C2C12 cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Some apparent chromodulin-like material formed during sample preparation, raising doubts about its identity as a pre-existing cellular signal.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[chromium-p17263387] X-ray absorption and EPR spectroscopic studies of the biotransformations of chromium(VI) in mammalian cells. Is chromodulin an artifact of isolation methods? (2007). https://pubmed.ncbi.nlm.nih.gov/17263387/ DOI: 10.1021/ja063792r","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Intact and lysed cell preparations","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"0003f6e5-627d-5979-bf5a-9c68a8c1476f","evidence_kind":"source_excerpt","locator":"Lines 237-248","start_line":237,"end_line":248,"excerpt":"### chromium-chromodulin-isolation-artifact\nMost Cr(III) formed in Cr(VI)-treated cells was associated with high-molecular-mass ligands; cell lysis redistributed chromium into a low-molecular-weight fraction spectroscopically similar to reported chromodulin.\nCondition category: normal\nnutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Some apparent chromodulin-like material formed during sample preparation, raising doubts about its identity as a pre-existing cellular signal.\norganism: Human A549/HepG2, hamster V79 and mouse C2C12 cells\ntissue_or_cell_type: Intact and lysed cell preparations\nexperimental_model: X-ray absorption and EPR before and after cell fractionation\nlimitations: The artifact evidence concerns chromium(VI)-exposed cells and the tested isolation procedures. It does not negate the activity measured when an isolated peptide preparation is added to an enzyme assay.\nexposure: Cr(VI)-treated cells; comparisons with model Cr(III) complexes\nevidence_span: {\"source_cache\": \"artifacts/chromium-research/17263387.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"912905b2fefe0745017faae62124fe077d3944cde635ae1012ff76fc33094b35\", \"start_char\": 0, \"end_char\": 1638, \"text_sha256\": \"912905b2fefe0745017faae62124fe077d3944cde635ae1012ff76fc33094b35\"}\n[chromium-p17263387] X-ray absorption and EPR spectroscopic studies of the biotransformations of chromium(VI) in mammalian cells. Is chromodulin an artifact of isolation methods? (2007). https://pubmed.ncbi.nlm.nih.gov/17263387/ DOI: 10.1021/ja063792r","model_system":"X-ray absorption and EPR before and after cell fractionation","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [chromium-p17263387] X-ray absorption and EPR spectroscopic studies of the biotransformations of chromium(VI) in mammalian cells. Is chromodulin an artifact of isolation methods? (2007). https://pubmed.ncbi.nlm.nih.gov/17263387/ DOI: 10.1021/ja063792r","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":[{"id":"a8b3a53d-f407-51ba-8153-a55db7c2c541","title":"Is isolated chromodulin a pre-existing cellular chromium signal or an extraction product?","kind":"contradiction","status":"open","why":"Early isolation work interpreted a bovine-liver low-molecular-weight chromium fraction as a natural candidate for biologically active chromium. Later intact-cell versus lysate spectroscopy showed metal redistribution during extraction and a resulting chromodulin-like fraction, directly challenging that interpretation. The later experiments used Cr(VI)-exposed cells; the exposure and isolation conditions must remain visible.","resolution":"Keep the isolation finding and the preparation-artifact evidence. The observed kinase activity of an added isolate can be recorded, while a required endogenous human chromodulin signaling cycle remains unproven. Do not convert this literature disagreement into a correction of draft wording.","created_at":"2026-09-17 19:32:27","record_type":"conflict","display_label":"Recorded conflict","record_url":"/conflicts/a8b3a53d-f407-51ba-8153-a55db7c2c541","sides":[{"conflict_id":"a8b3a53d-f407-51ba-8153-a55db7c2c541","ordinal":0,"label":"Researchers isolated a chromium-binding peptide fraction, but its structure and origin inside living cells were not fully settled.","revision_id":"22893798-8329-5295-9c9d-82169032fc79","start_line":224,"end_line":235,"quote":"### chromium-chromodulin-isolate\nThe bovine-liver low-molecular-weight isolate contained approximately four Cr(III) ions per peptide, with spectra consistent with carboxylate-supported metal assemblies; one tetranuclear versus two dinuclear assemblies was unresolved.\nCondition category: normal\nnutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Researchers isolated a chromium-binding peptide fraction, but its structure and origin inside living cells were not fully settled.\norganism: Bovine liver isolate\ntissue_or_cell_type: Purified fraction outside intact cells\nexperimental_model: Isolation and spectroscopy of a bovine-liver chromium-containing peptide fraction\nlimitations: The paper interpreted the isolate as naturally occurring; later work questioned whether similar low-molecular-weight species arise during extraction. Exact nuclearity was not resolved by this study.\nexposure: Spectroscopic characterization of an isolate with approximately four Cr(III) ions per peptide\nevidence_span: {\"source_cache\": \"artifacts/chromium-research/9056266.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"36be61aa6271d3491a4432d31d5ea6524a059fcc1f1ba1e0acac5f175f711a06\", \"start_char\": 0, \"end_char\": 791, \"text_sha256\": \"36be61aa6271d3491a4432d31d5ea6524a059fcc1f1ba1e0acac5f175f711a06\"}\n[chromium-p9056266] Isolation and characterization of a biologically active chromium oligopeptide from bovine liver. (1997). https://pubmed.ncbi.nlm.nih.gov/9056266/ DOI: 10.1006/abbi.1997.9878","source_key":"import-4d8e4781-3878-5818-8d0a-7dbd6e024555","source_title":"Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17)","claim_ids":["5e3e0632-23f5-5c82-b015-4680f1643b15"]},{"conflict_id":"a8b3a53d-f407-51ba-8153-a55db7c2c541","ordinal":1,"label":"Some apparent chromodulin-like material formed during sample preparation, raising doubts about its identity as a pre-existing cellular signal.","revision_id":"22893798-8329-5295-9c9d-82169032fc79","start_line":237,"end_line":248,"quote":"### chromium-chromodulin-isolation-artifact\nMost Cr(III) formed in Cr(VI)-treated cells was associated with high-molecular-mass ligands; cell lysis redistributed chromium into a low-molecular-weight fraction spectroscopically similar to reported chromodulin.\nCondition category: normal\nnutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Some apparent chromodulin-like material formed during sample preparation, raising doubts about its identity as a pre-existing cellular signal.\norganism: Human A549/HepG2, hamster V79 and mouse C2C12 cells\ntissue_or_cell_type: Intact and lysed cell preparations\nexperimental_model: X-ray absorption and EPR before and after cell fractionation\nlimitations: The artifact evidence concerns chromium(VI)-exposed cells and the tested isolation procedures. It does not negate the activity measured when an isolated peptide preparation is added to an enzyme assay.\nexposure: Cr(VI)-treated cells; comparisons with model Cr(III) complexes\nevidence_span: {\"source_cache\": \"artifacts/chromium-research/17263387.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"912905b2fefe0745017faae62124fe077d3944cde635ae1012ff76fc33094b35\", \"start_char\": 0, \"end_char\": 1638, \"text_sha256\": \"912905b2fefe0745017faae62124fe077d3944cde635ae1012ff76fc33094b35\"}\n[chromium-p17263387] X-ray absorption and EPR spectroscopic studies of the biotransformations of chromium(VI) in mammalian cells. Is chromodulin an artifact of isolation methods? (2007). https://pubmed.ncbi.nlm.nih.gov/17263387/ DOI: 10.1021/ja063792r","source_key":"import-4d8e4781-3878-5818-8d0a-7dbd6e024555","source_title":"Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17)","claim_ids":["91dc5e47-7d79-5db4-b8f4-59f142cfd389"]}]}],"corrections":[],"research":null}