{"id":"4201c11d-0896-5875-b3ff-95c6522b0884","stable_key":"0f17db03-207f-5910-ac8e-13dfc2f378ce:mg-tkt-loading-lag","predicate":"supports","statement":"Human erythrocyte apo-transketolase activation kinetics supported slow Mg-ThDP binding followed by slow isomerization.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"a94f0d69-4d52-55e5-bdf5-eaf108ce2977","mechanism_event_label":"The cofactor-loading complex contains ThDP and magnesium, not ATP.","subject":{"id":"0f84e417-7ecb-57f1-87da-5edc2d957cb2","slug":"mg-thdp","display_name":"Magnesium-thiamine diphosphate complex","entity_type_key":"chemical_species"},"object":{"id":"0c6821a0-f5ad-5057-9af6-5379fde69525","slug":"tkt-cofactor-loading","display_name":"Transketolase cofactor loading","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"a94f0d69-4d52-55e5-bdf5-eaf108ce2977","stable_key":"0f17db03-207f-5910-ac8e-13dfc2f378ce:mg-tkt-loading-lag-event","event_type":"biochemical_relationship","label":"The cofactor-loading complex contains ThDP and magnesium, not ATP.","description":"Human erythrocyte apo-transketolase activation kinetics supported slow Mg-ThDP binding followed by slow isomerization.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"c95c645c-ae67-5911-871e-4f796a17faec","slug":"tkt","display_name":"Human transketolase","entity_type_key":"protein"},"role":"enzyme","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"187db168-8028-5ce6-9f8b-4bc61ebad1a0","slug":"thiamine-diphosphate","display_name":"Thiamine diphosphate","entity_type_key":"small_molecule"},"role":"cofactor","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"role":"cofactor-associated metal","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"0f84e417-7ecb-57f1-87da-5edc2d957cb2","slug":"mg-thdp","display_name":"Magnesium-thiamine diphosphate complex","entity_type_key":"chemical_species"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"0c6821a0-f5ad-5057-9af6-5379fde69525","slug":"tkt-cofactor-loading","display_name":"Transketolase cofactor loading","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":4,"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":"Human erythrocyte apo-transketolase reconstitution kinetics.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This is a kinetic interpretation; it differs from yeast reconstitution involving rate-limiting dimerization.","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 cofactor-loading complex contains ThDP and magnesium, not ATP.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[booth-1993-tkt] Reconstitution of holotransketolase is by a thiamin-diphosphate-magnesium complex (1993). https://pubmed.ncbi.nlm.nih.gov/8243472/ DOI: 10.1111/j.1432-1033.1993.tb18373.x","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Erythrocyte apoenzyme","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"e97c13c8-6a9a-5b1f-aa6e-79597192476c","evidence_kind":"source_excerpt","locator":"Lines 577-587","start_line":577,"end_line":587,"excerpt":"### mg-tkt-loading-lag\nHuman erythrocyte apo-transketolase activation kinetics supported slow Mg-ThDP binding followed by slow isomerization.\nCondition category: normal\nnutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The cofactor-loading complex contains ThDP and magnesium, not ATP.\norganism: Homo sapiens\ntissue_or_cell_type: Erythrocyte apoenzyme\nexperimental_model: Human erythrocyte apo-transketolase reconstitution kinetics.\nlimitations: This is a kinetic interpretation; it differs from yeast reconstitution involving rate-limiting dimerization.\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[booth-1993-tkt] Reconstitution of holotransketolase is by a thiamin-diphosphate-magnesium complex (1993). https://pubmed.ncbi.nlm.nih.gov/8243472/ DOI: 10.1111/j.1432-1033.1993.tb18373.x","model_system":"Human erythrocyte apo-transketolase reconstitution kinetics.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [booth-1993-tkt] Reconstitution of holotransketolase is by a thiamin-diphosphate-magnesium complex (1993). https://pubmed.ncbi.nlm.nih.gov/8243472/ DOI: 10.1111/j.1432-1033.1993.tb18373.x","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}