{"id":"125176a0-385f-582d-a107-4b6c7c71a4ee","stable_key":"46d15d9e-d3b5-544d-ba01-b785aa3e4f42:b1-tpk1-atp-amp-stoichiometry","predicate":"donates-diphosphoryl-group-to","statement":"TPK1 activation transfers ATP-derived diphosphoryl to thiamine, yielding ThDP and AMP in a magnesium-dependent reaction.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"74b1a5b2-44b9-56ec-bde1-8cea9239cb1a","mechanism_event_label":"B1 activation uses ATP and releases AMP; it is not an ATP-to-ADP single-phosphate step.","subject":{"id":"58b974f1-d389-5bf6-81cd-889c44442c42","slug":"atp","display_name":"ATP","entity_type_key":"small_molecule"},"object":{"id":"36b7c3eb-068b-500f-af1c-078829df1ecc","slug":"thiamine","display_name":"Thiamine (vitamin B1)","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"74b1a5b2-44b9-56ec-bde1-8cea9239cb1a","stable_key":"46d15d9e-d3b5-544d-ba01-b785aa3e4f42:b1-tpk1-atp-amp-stoichiometry-event","event_type":"biochemical_relationship","label":"B1 activation uses ATP and releases AMP; 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it does not imply every later ThDP-binding event consumes ATP.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"curation_note","value_text":"Adds explicit phosphate-transfer/AMP-product detail to the existing magnesium collection.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence-scope","value_text":"Recombinant enzyme","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_locator","value_text":"Abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_spans","value_text":"[{\"source_document\": \"artifacts/thiamine_transport_sources/sambon-2022-tpk1-source-record.json\", \"source_field\": \"resultList.result[0].abstractText\", \"start_char\": 0, \"end_char\": 1689}]","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified His-tagged human TPK1; ATP/Mg kinetics and mutagenesis.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Overall chemistry does not resolve substrate-binding order.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Thiamine research collection; 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topical membership is not evidence of a direct dietary effect.\nplain_language: B1 activation uses ATP and releases AMP; it is not an ATP-to-ADP single-phosphate step.\norganism: Homo sapiens\ntissue_or_cell_type: Recombinant enzyme\nexperimental_model: Purified His-tagged human TPK1; ATP/Mg kinetics and mutagenesis.\nlimitations: Overall chemistry does not resolve substrate-binding order.\ncross_nutrient: Mg-dependent ATP chemistry activates B1; it does not imply every later ThDP-binding event consumes ATP.\nreaction: thiamine + ATP -> thiamine diphosphate + AMP\nrelated_existing_claim_keys: [\"mg-tpk1-thiamine-to-thdp\"]\ncuration_note: Adds explicit phosphate-transfer/AMP-product detail to the existing magnesium collection.\nevidence_spans: [{\"source_document\": \"artifacts/thiamine_transport_sources/sambon-2022-tpk1-source-record.json\", \"source_field\": \"resultList.result[0].abstractText\", \"start_char\": 0, \"end_char\": 1689}]\nevidence_locator: Abstract\nevidence-scope: Recombinant enzyme\n[onozuka-2003-tpk1] Steady-state kinetics and mutational studies of recombinant human thiamin pyrophosphokinase (2003). https://pubmed.ncbi.nlm.nih.gov/12953792/ DOI: 10.3177/jnsv.49.156\n[sambon-2022-tpk1] Product inhibition of mammalian thiamine pyrophosphokinase is an important mechanism for maintaining thiamine diphosphate homeostasis (2022). https://doi.org/10.1016/j.bbagen.2021.130071 DOI: 10.1016/j.bbagen.2021.130071","model_system":"Purified His-tagged human TPK1; 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Study references: [onozuka-2003-tpk1] Steady-state kinetics and mutational studies of recombinant human thiamin pyrophosphokinase (2003). https://pubmed.ncbi.nlm.nih.gov/12953792/ DOI: 10.3177/jnsv.49.156; [sambon-2022-tpk1] Product inhibition of mammalian thiamine pyrophosphokinase is an important mechanism for maintaining thiamine diphosphate homeostasis (2022). https://doi.org/10.1016/j.bbagen.2021.130071 DOI: 10.1016/j.bbagen.2021.130071","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"158d2c03-ac8c-589f-8270-c468165ae346","stable_key":"import-46d15d9e-d3b5-544d-ba01-b785aa3e4f42","title":"Thiamine: mechanisms, deficiency and nutrient interactions (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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