{"id":"6a51f1b1-33f2-5143-a597-514d032d234a","stable_key":"4d8e4781-3878-5818-8d0a-7dbd6e024555:chromium-membrane-phosphatase-activation","predicate":"activates","statement":"The isolate increased membrane phosphotyrosine-phosphatase activity in proportion to the amount added, while the isolate itself had no intrinsic phosphatase activity.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"89270e26-5445-540e-9c89-c9acf70282b3","mechanism_event_label":"This experiment increased a phosphatase activity; the exact enzyme identity remained unresolved.","subject":{"id":"ea6e4ab5-46a0-5fb0-9b10-5a7b0b31024b","slug":"bovine-lmwcr-isolate","display_name":"Bovine liver low-molecular-weight chromium-binding isolate / chromodulin candidate","entity_type_key":"protein_complex"},"object":{"id":"2d38fd40-95a2-5d79-aeb0-863de97ef0c9","slug":"adipocyte-membrane-phosphotyrosine-phosphatases","display_name":"Adipocyte membrane phosphotyrosine phosphatases (identity unresolved)","entity_type_key":"protein_family"},"evidence_count":1,"mechanism_event":{"id":"89270e26-5445-540e-9c89-c9acf70282b3","stable_key":"4d8e4781-3878-5818-8d0a-7dbd6e024555:chromium-membrane-phosphatase-activation-event","event_type":"biochemical_relationship","label":"This experiment increased a phosphatase activity; the exact enzyme identity remained unresolved.","description":"The isolate increased membrane phosphotyrosine-phosphatase activity in proportion to the amount added, while the isolate itself had no intrinsic phosphatase activity.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"ea6e4ab5-46a0-5fb0-9b10-5a7b0b31024b","slug":"bovine-lmwcr-isolate","display_name":"Bovine liver low-molecular-weight chromium-binding isolate / chromodulin candidate","entity_type_key":"protein_complex"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"2d38fd40-95a2-5d79-aeb0-863de97ef0c9","slug":"adipocyte-membrane-phosphotyrosine-phosphatases","display_name":"Adipocyte membrane phosphotyrosine phosphatases (identity unresolved)","entity_type_key":"protein_family"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/chromium-research/8841143.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"04928cdcbe3e2a282fa43f6a987d1846c6a4e882a6834542b19578b43f8f8322\", \"start_char\": 0, \"end_char\": 942, \"text_sha256\": \"04928cdcbe3e2a282fa43f6a987d1846c6a4e882a6834542b19578b43f8f8322\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Membrane phosphatase kinetics and inhibitor profiling","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Added low-molecular-weight chromium-binding preparation","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"The phosphatase was not molecularly identified. Inhibitor behavior suggested similarity to PTP1A′ or PTP1B but does not justify assigning this result to a specific gene. Activation here is not proof of universal PTP1B inhibition.","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":"Bovine liver isolate; adipocyte membranes","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"This experiment increased a phosphatase activity; the exact enzyme identity remained unresolved.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[chromium-p8841143] A biologically active form of chromium may activate a membrane phosphotyrosine phosphatase (PTP). (1996). https://pubmed.ncbi.nlm.nih.gov/8841143/ DOI: 10.1021/bi960328y","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cell-membrane enzyme preparation","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"1ebf44a9-c69e-543b-9336-52c517d07b26","evidence_kind":"source_excerpt","locator":"Lines 289-300","start_line":289,"end_line":300,"excerpt":"### chromium-membrane-phosphatase-activation\nThe isolate increased membrane phosphotyrosine-phosphatase activity in proportion to the amount added, while the isolate itself had no intrinsic phosphatase activity.\nCondition category: normal\nnutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: This experiment increased a phosphatase activity; the exact enzyme identity remained unresolved.\norganism: Bovine liver isolate; adipocyte membranes\ntissue_or_cell_type: Cell-membrane enzyme preparation\nexperimental_model: Membrane phosphatase kinetics and inhibitor profiling\nlimitations: The phosphatase was not molecularly identified. Inhibitor behavior suggested similarity to PTP1A′ or PTP1B but does not justify assigning this result to a specific gene. Activation here is not proof of universal PTP1B inhibition.\nexposure: Added low-molecular-weight chromium-binding preparation\nevidence_span: {\"source_cache\": \"artifacts/chromium-research/8841143.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"04928cdcbe3e2a282fa43f6a987d1846c6a4e882a6834542b19578b43f8f8322\", \"start_char\": 0, \"end_char\": 942, \"text_sha256\": \"04928cdcbe3e2a282fa43f6a987d1846c6a4e882a6834542b19578b43f8f8322\"}\n[chromium-p8841143] A biologically active form of chromium may activate a membrane phosphotyrosine phosphatase (PTP). (1996). https://pubmed.ncbi.nlm.nih.gov/8841143/ DOI: 10.1021/bi960328y","model_system":"Membrane phosphatase kinetics and inhibitor profiling","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [chromium-p8841143] A biologically active form of chromium may activate a membrane phosphotyrosine phosphatase (PTP). (1996). https://pubmed.ncbi.nlm.nih.gov/8841143/ DOI: 10.1021/bi960328y","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. 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