{"id":"5b1ae96a-5cf5-5aec-8b4c-01f6545b83c0","stable_key":"f992b796-377d-53bf-a39b-7e5d41dbe194:b5-trans-lipoate-inhibits-biotin","predicate":"inhibits","statement":"Oxidized alpha-lipoic acid inhibited human SMVT-mediated radiolabeled biotin uptake with an IC50 of 9.1 micromolar in the 2026 HEK293T assay.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"51a4cb61-5c33-53f5-8a9e-43039f6a4735","mechanism_event_label":"Oxidized alpha-lipoic acid competed with biotin uptake in the SMVT cell assay.","subject":{"id":"ab091982-3acb-5a87-80fb-85dfe292c1e0","slug":"lipoic-acid","display_name":"Lipoic acid","entity_type_key":"small_molecule"},"object":{"id":"d25f4daa-5529-568f-b319-7c30e444914b","slug":"cellular-biotin-uptake","display_name":"Cellular biotin uptake","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"51a4cb61-5c33-53f5-8a9e-43039f6a4735","stable_key":"f992b796-377d-53bf-a39b-7e5d41dbe194:b5-trans-lipoate-inhibits-biotin-event","event_type":"biochemical_relationship","label":"Oxidized alpha-lipoic acid competed with biotin uptake in the SMVT cell assay.","description":"Oxidized alpha-lipoic acid inhibited human SMVT-mediated radiolabeled biotin uptake with an IC50 of 9.1 micromolar in the 2026 HEK293T assay.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"3bd59e38-e6b1-5223-b4de-faa33835f5bc","slug":"slc5a6","display_name":"Human sodium-dependent multivitamin transporter / SLC5A6","entity_type_key":"protein"},"role":"shared_transporter","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"37a8e96b-f95b-5ba7-a0bc-8ed3cfaf5fd8","slug":"biotin","display_name":"Biotin","entity_type_key":"small_molecule"},"role":"competed_transport_substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"7bc62072-9517-5563-a3b8-8c5ab64a464b","slug":"pantothenate","display_name":"Pantothenate (vitamin B5)","entity_type_key":"small_molecule"},"role":"other_shared_substrate","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"ab091982-3acb-5a87-80fb-85dfe292c1e0","slug":"lipoic-acid","display_name":"Lipoic acid","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"d25f4daa-5529-568f-b319-7c30e444914b","slug":"cellular-biotin-uptake","display_name":"Cellular biotin uptake","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"true","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Cryo-EM of engineered human SMVT with nanobody-assisted alignment; functional uptake assays in HEK293T cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Biotin uptake assay: 5 micromolar unlabeled biotin plus [3H]biotin at a 300:1 molar ratio; 30 degrees C for ten minutes; inhibitor concentration varied.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"In-vitro IC50 depends on tracer/substrate concentration and expression conditions; it is not a human supplement dose, affinity constant, or threshold for biotin deficiency.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Pantothenic acid (vitamin B5) research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"pantothenate","display_name":"Pantothenate (vitamin B5)","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Oxidized alpha-lipoic acid competed with biotin uptake in the SMVT cell assay.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[b5-trans-structure2026] Structural basis for multivitamin recognition and transport by human SMVT. (2026). https://pubmed.ncbi.nlm.nih.gov/42364996/ DOI: 10.1038/s41467-026-74948-3","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"HEK293T cells expressing human SMVT","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"f1d1216d-d9a9-5acc-a4d3-c9a4639c6d19","evidence_kind":"source_excerpt","locator":"Lines 444-455","start_line":444,"end_line":455,"excerpt":"### b5-trans-lipoate-inhibits-biotin\nOxidized alpha-lipoic acid inhibited human SMVT-mediated radiolabeled biotin uptake with an IC50 of 9.1 micromolar in the 2026 HEK293T assay.\nCondition category: normal\nnutrient_topic: Pantothenic acid (vitamin B5) research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Oxidized alpha-lipoic acid competed with biotin uptake in the SMVT cell assay.\norganism: Homo sapiens\ntissue_or_cell_type: HEK293T cells expressing human SMVT\nexperimental_model: Cryo-EM of engineered human SMVT with nanobody-assisted alignment; functional uptake assays in HEK293T cells\nlimitations: In-vitro IC50 depends on tracer/substrate concentration and expression conditions; it is not a human supplement dose, affinity constant, or threshold for biotin deficiency.\nexposure: Biotin uptake assay: 5 micromolar unlabeled biotin plus [3H]biotin at a 300:1 molar ratio; 30 degrees C for ten minutes; inhibitor concentration varied.\ncross_nutrient: true\n[b5-trans-structure2026] Structural basis for multivitamin recognition and transport by human SMVT. 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