{"id":"d205f464-1224-5010-af96-5019deba0582","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:transport-rfk-phosphorylation","predicate":"converts","statement":"Human RFK phosphorylates riboflavin to FMN using ATP, yielding ADP; this precedes FLAD1-mediated FAD synthesis.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"73a98778-5bcc-59a6-b00a-195e16555b8d","mechanism_event_label":"RFK performs the first activation step from riboflavin to FMN.","subject":{"id":"96f56b42-6b88-54d2-b35c-24a1f52fddde","slug":"rfk","display_name":"Riboflavin kinase / RFK","entity_type_key":"protein"},"object":{"id":"86eb1eee-a8d1-539c-8c17-0911f69b6f1b","slug":"riboflavin","display_name":"Riboflavin (vitamin B2)","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"73a98778-5bcc-59a6-b00a-195e16555b8d","stable_key":"548ab9d6-3a9b-5bed-879c-17d03813b636:transport-rfk-phosphorylation-event","event_type":"biochemical_relationship","label":"RFK performs the first activation step from riboflavin to FMN.","description":"Human RFK phosphorylates riboflavin to FMN using ATP, yielding ADP; this precedes FLAD1-mediated FAD synthesis.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"96f56b42-6b88-54d2-b35c-24a1f52fddde","slug":"rfk","display_name":"Riboflavin kinase / RFK","entity_type_key":"protein"},"role":"enzyme","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"86eb1eee-a8d1-539c-8c17-0911f69b6f1b","slug":"riboflavin","display_name":"Riboflavin (vitamin B2)","entity_type_key":"small_molecule"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"58b974f1-d389-5bf6-81cd-889c44442c42","slug":"atp","display_name":"ATP","entity_type_key":"small_molecule"},"role":"phosphoryl-donor","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"d3eacf85-1a35-546d-bd30-161474dd9691","slug":"fmn","display_name":"Flavin mononucleotide","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"136c3764-1b93-5f79-8673-9001cab9bc3d","slug":"adp","display_name":"Adenosine diphosphate","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_location","value_text":"Abstract and product-bound structure","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human RFK structural and catalytic mechanism study","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Purified RFK with flavin and adenine nucleotide ligands.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Reaction chemistry does not imply RFK controls every tissue flavin pool to the same extent.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Riboflavin research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"riboflavin","display_name":"Riboflavin (vitamin B2)","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"RFK performs the first activation step from riboflavin to FMN.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[transport-rfk-2003] Ligand binding-induced conformational changes in riboflavin kinase: structural basis for the ordered mechanism. (2003). https://pubmed.ncbi.nlm.nih.gov/14580199/ DOI: 10.1021/bi035450t","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified protein","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"ae80ff78-07c1-52d1-a7fa-19a8ba18d58f","evidence_kind":"source_excerpt","locator":"Lines 293-304","start_line":293,"end_line":304,"excerpt":"### transport-rfk-phosphorylation\nHuman RFK phosphorylates riboflavin to FMN using ATP, yielding ADP; this precedes FLAD1-mediated FAD synthesis.\nCondition category: normal\nnutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: RFK performs the first activation step from riboflavin to FMN.\norganism: Homo sapiens\ntissue_or_cell_type: Purified protein\nexperimental_model: Human RFK structural and catalytic mechanism study\nlimitations: Reaction chemistry does not imply RFK controls every tissue flavin pool to the same extent.\nexposure: Purified RFK with flavin and adenine nucleotide ligands.\nevidence_location: Abstract and product-bound structure\n[transport-rfk-2003] Ligand binding-induced conformational changes in riboflavin kinase: structural basis for the ordered mechanism. (2003). https://pubmed.ncbi.nlm.nih.gov/14580199/ DOI: 10.1021/bi035450t","model_system":"Human RFK structural and catalytic mechanism study","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [transport-rfk-2003] Ligand binding-induced conformational changes in riboflavin kinase: structural basis for the ordered mechanism. (2003). https://pubmed.ncbi.nlm.nih.gov/14580199/ DOI: 10.1021/bi035450t","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"4f7c9578-82bf-5e2d-b5c4-72a79fb4f6af","stable_key":"import-548ab9d6-3a9b-5bed-879c-17d03813b636","title":"Riboflavin: 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. Not publisher full text.","file_path":"","sha256":"680cb6bc8249877f2410f551807f10d390fdd719014137d7414ba3420e29228d","revision_id":"7a61e299-908d-5372-860b-99ed190f9d7a","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}