{"id":"4b4f91cc-b77a-51de-bc76-551df7cda882","stable_key":"e69ef6a0-0e23-5eac-aca1-cf333781b962:ino-impa-high-magnesium","predicate":"inhibits","statement":"High Mg2+ concentrations inhibited human inositol monophosphatase uncompetitively with respect to substrate.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"fe63d2c5-e72a-53cc-b988-1d9c6c0846c7","mechanism_event_label":"An enzyme can need a mineral yet become inhibited when its concentration is too high.","subject":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"object":{"id":"3f404867-317e-5b5c-92a7-9b6e0411dec3","slug":"impa1","display_name":"IMPA1 (human inositol monophosphatase 1)","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"fe63d2c5-e72a-53cc-b988-1d9c6c0846c7","stable_key":"e69ef6a0-0e23-5eac-aca1-cf333781b962:ino-impa-high-magnesium-event","event_type":"biochemical_relationship","label":"An enzyme can need a mineral yet become inhibited when its concentration is too high.","description":"High Mg2+ concentrations inhibited human inositol monophosphatase uncompetitively with respect to substrate.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"3f404867-317e-5b5c-92a7-9b6e0411dec3","slug":"impa1","display_name":"IMPA1 (human inositol monophosphatase 1)","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/inositol-research/8223565.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"945d1d5166ce6410cd69984d93aebf127b635dcfcebddba31f0e8cc8b1c304a5\", \"start_char\": 0, \"end_char\": 1621, \"text_sha256\": \"945d1d5166ce6410cd69984d93aebf127b635dcfcebddba31f0e8cc8b1c304a5\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Site-directed mutagenesis and enzyme kinetics","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Magnesium and lithium titrations","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Biochemical concentration dependence; neither lithium treatment mechanism nor magnesium supplementation response is established by this assay alone.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Inositol research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"inositol","display_name":"Inositol (stereoisomer family)","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Human recombinant protein","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"An enzyme can need a mineral yet become inhibited when its concentration is too high.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[ino-p8223565] Probing the role of metal ions in the mechanism of inositol monophosphatase by site-directed mutagenesis. (1993). https://pubmed.ncbi.nlm.nih.gov/8223565/ DOI: 10.1111/j.1432-1033.1993.tb18244.x","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified IMPA1","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"9d7626ae-47cc-59d2-b4d1-a473aff3efae","evidence_kind":"source_excerpt","locator":"Lines 262-273","start_line":262,"end_line":273,"excerpt":"### ino-impa-high-magnesium\nHigh Mg2+ concentrations inhibited human inositol monophosphatase uncompetitively with respect to substrate.\nCondition category: normal\nnutrient_topic: Inositol research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: An enzyme can need a mineral yet become inhibited when its concentration is too high.\norganism: Human recombinant protein\ntissue_or_cell_type: Purified IMPA1\nexperimental_model: Site-directed mutagenesis and enzyme kinetics\nlimitations: Biochemical concentration dependence; neither lithium treatment mechanism nor magnesium supplementation response is established by this assay alone.\nexposure: Magnesium and lithium titrations\nevidence_span: {\"source_cache\": \"artifacts/inositol-research/8223565.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"945d1d5166ce6410cd69984d93aebf127b635dcfcebddba31f0e8cc8b1c304a5\", \"start_char\": 0, \"end_char\": 1621, \"text_sha256\": \"945d1d5166ce6410cd69984d93aebf127b635dcfcebddba31f0e8cc8b1c304a5\"}\n[ino-p8223565] Probing the role of metal ions in the mechanism of inositol monophosphatase by site-directed mutagenesis. (1993). https://pubmed.ncbi.nlm.nih.gov/8223565/ DOI: 10.1111/j.1432-1033.1993.tb18244.x","model_system":"Site-directed mutagenesis and enzyme kinetics","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [ino-p8223565] Probing the role of metal ions in the mechanism of inositol monophosphatase by site-directed mutagenesis. (1993). https://pubmed.ncbi.nlm.nih.gov/8223565/ DOI: 10.1111/j.1432-1033.1993.tb18244.x","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"d590c659-b774-50e6-9f1d-aff61d5f7c9c","stable_key":"import-e69ef6a0-0e23-5eac-aca1-cf333781b962","title":"Inositol: synthesis, signaling, mineral interactions and conditional deficiency (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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