{"id":"61eb6816-b8b1-5067-8e4d-b2c80e5df367","stable_key":"0f17db03-207f-5910-ac8e-13dfc2f378ce:mg-tkt-tight-cofactor-retention","predicate":"retains","statement":"Recombinant human TKT retained ThDP and Ca2+ strongly under cofactor-removal conditions used in the study.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"21f2e8e8-cacc-5b09-b0ed-f3793f68576c","mechanism_event_label":"The enzyme can retain loaded cofactors; free-metal changes need not immediately strip them away.","subject":{"id":"c95c645c-ae67-5911-871e-4f796a17faec","slug":"tkt","display_name":"Human transketolase","entity_type_key":"protein"},"object":{"id":"187db168-8028-5ce6-9f8b-4bc61ebad1a0","slug":"thiamine-diphosphate","display_name":"Thiamine diphosphate","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"21f2e8e8-cacc-5b09-b0ed-f3793f68576c","stable_key":"0f17db03-207f-5910-ac8e-13dfc2f378ce:mg-tkt-tight-cofactor-retention-event","event_type":"biochemical_relationship","label":"The enzyme can retain loaded cofactors; free-metal changes need not immediately strip them away.","description":"Recombinant human TKT retained ThDP and Ca2+ strongly under cofactor-removal conditions used in the study.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"e359bc15-e675-5d83-b0fe-1d70814e130b","slug":"calcium-ion","display_name":"Calcium ion","entity_type_key":"ion"},"role":"retained metal","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"c95c645c-ae67-5911-871e-4f796a17faec","slug":"tkt","display_name":"Human transketolase","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"187db168-8028-5ce6-9f8b-4bc61ebad1a0","slug":"thiamine-diphosphate","display_name":"Thiamine diphosphate","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human TKT crystallography, kinetics and NMR.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Retention is preparation- and protocol-specific; this is not a measurement of in vivo Mg depletion.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Magnesium research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"magnesium","display_name":"Magnesium","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The enzyme can retain loaded cofactors; free-metal changes need not immediately strip them away.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[mitschke-2010-tkt] The Crystal Structure of Human Transketolase and New Insights into Its Mode of Action (2010). https://pmc.ncbi.nlm.nih.gov/articles/PMC2951230/ DOI: 10.1074/jbc.M110.149955","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified recombinant TKT","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"a55bf52a-2e0d-5aaa-9099-389c3050749f","evidence_kind":"source_excerpt","locator":"Lines 601-611","start_line":601,"end_line":611,"excerpt":"### mg-tkt-tight-cofactor-retention\nRecombinant human TKT retained ThDP and Ca2+ strongly under cofactor-removal conditions used in the study.\nCondition category: normal\nnutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The enzyme can retain loaded cofactors; free-metal changes need not immediately strip them away.\norganism: Homo sapiens\ntissue_or_cell_type: Purified recombinant TKT\nexperimental_model: Recombinant human TKT crystallography, kinetics and NMR.\nlimitations: Retention is preparation- and protocol-specific; this is not a measurement of in vivo Mg depletion.\ncross_nutrient: Magnesium availability supports vitamin B1 activation or cofactor use in the specified preparation; this does not establish a dietary threshold or universal treatment failure.\n[mitschke-2010-tkt] The Crystal Structure of Human Transketolase and New Insights into Its Mode of Action (2010). https://pmc.ncbi.nlm.nih.gov/articles/PMC2951230/ DOI: 10.1074/jbc.M110.149955","model_system":"Recombinant human TKT crystallography, kinetics and NMR.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [mitschke-2010-tkt] The Crystal Structure of Human Transketolase and New Insights into Its Mode of Action (2010). https://pmc.ncbi.nlm.nih.gov/articles/PMC2951230/ DOI: 10.1074/jbc.M110.149955","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"dd101e28-1a2e-5a48-9d1e-809c77514866","stable_key":"import-0f17db03-207f-5910-ac8e-13dfc2f378ce","title":"Magnesium: cross-nutrient mechanisms and 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. Not publisher full text.","file_path":"","sha256":"e111c412f57143a17e8e65e74e8f7888b5bb9a61099873f4767f527fac19bb07","revision_id":"6b7f04f2-66ed-5859-955f-c2b50d4bf041","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}