{"id":"985d5a59-b520-5efe-8081-19a6947bead5","stable_key":"335be270-ea4a-5c8e-ad04-964fd22a439e:vanadium-pervanadate-cysteine","predicate":"irreversibly_oxidizes","statement":"Pervanadate irreversibly inhibited PTP1B by oxidation of its catalytic cysteine, supported by mass spectrometry.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"e8c3f790-39da-57b7-b5d8-c5a279d211ef","mechanism_event_label":"The peroxide-containing species disables the enzyme through a different mechanism.","subject":{"id":"f1faad21-091c-5b03-a03c-a20011d36fef","slug":"pervanadate","display_name":"Pervanadate / peroxovanadium(V) assay species","entity_type_key":"chemical_species"},"object":{"id":"58af4c7b-a5f4-540c-85eb-28a6161d45e7","slug":"ptp1b-1997-assay-preparation","display_name":"PTP1B preparation in the 1997 vanadate inhibition study","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"e8c3f790-39da-57b7-b5d8-c5a279d211ef","stable_key":"335be270-ea4a-5c8e-ad04-964fd22a439e:vanadium-pervanadate-cysteine-event","event_type":"observed_relationship","label":"The peroxide-containing species disables the enzyme through a different mechanism.","description":"Pervanadate irreversibly inhibited PTP1B by oxidation of its catalytic cysteine, supported by mass spectrometry.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"f1faad21-091c-5b03-a03c-a20011d36fef","slug":"pervanadate","display_name":"Pervanadate / peroxovanadium(V) assay species","entity_type_key":"chemical_species"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"58af4c7b-a5f4-540c-85eb-28a6161d45e7","slug":"ptp1b-1997-assay-preparation","display_name":"PTP1B preparation in the 1997 vanadate inhibition study","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"c5cbad45-22c6-594b-ab6b-71880dab1b24","slug":"vanadium","display_name":"Vanadium","entity_type_key":"nutrient_element"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"da9d64bc-69d4-5d97-90a4-8f0ed03e0ac8","slug":"hydrogen-peroxide","display_name":"Hydrogen peroxide","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified PTP1B kinetic and mass-spectrometric experiments.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Do not assign this irreversible oxidation to all vanadate exposures or dietary vanadium.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vanadium collection; molecular form, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vanadium","display_name":"Vanadium","entity_type_key":"nutrient_element"}},{"dimension":"plain_language","value_text":"The peroxide-containing species disables the enzyme through a different mechanism.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Mechanism of inhibition of protein-tyrosine phosphatases by vanadate and pervanadate. · 1997 · https://pubmed.ncbi.nlm.nih.gov/8995372/ · DOI 10.1074/jbc.272.2.843","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"cdaf932d-c78c-5cc9-ba98-f6030fe9bb0c","evidence_kind":"source_excerpt","locator":"Lines 30-36","start_line":30,"end_line":36,"excerpt":"## vanadium-pervanadate-cysteine\nThe peroxide-containing species disables the enzyme through a different mechanism.\nPervanadate irreversibly inhibited PTP1B by oxidation of its catalytic cysteine, supported by mass spectrometry.\nModel: Purified PTP1B kinetic and mass-spectrometric experiments.\nLimitations: Do not assign this irreversible oxidation to all vanadate exposures or dietary vanadium.\nEvidence access: Primary abstract\nMechanism of inhibition of protein-tyrosine phosphatases by vanadate and pervanadate. · 1997 · https://pubmed.ncbi.nlm.nih.gov/8995372/ · DOI 10.1074/jbc.272.2.843","model_system":"Purified PTP1B kinetic and mass-spectrometric experiments.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"e4d5d0ba-529b-540f-96ed-e719d116ccfd","stable_key":"import-335be270-ea4a-5c8e-ad04-964fd22a439e","title":"Vanadium: speciation, phosphate-sensitive enzymes and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. 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