{"id":"2a7b0ab4-119f-524f-b745-1577b84e6036","stable_key":"6cdb37aa-8998-5ea8-829d-4f995caf98fc:l-carnitine-crat-pdh","predicate":"stimulates_conditionally","statement":"Adding carnitine stimulated PDH activity 1.8-fold in control muscle mitochondria but did not stimulate it in Crat-null mitochondria.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"3e839b9f-7bb3-55f3-b10e-0564dfe2ce24","mechanism_event_label":"Carnitine needs the acetyl-transfer enzyme to relieve this brake on glucose oxidation.","subject":{"id":"6e34c035-9371-578f-b799-fd2a14e9e40f","slug":"l-carnitine","display_name":"L-Carnitine","entity_type_key":"small_molecule"},"object":{"id":"d8a37877-cf9f-5fd1-8695-3d82ef6868ab","slug":"mouse-muscle-pdh-activity","display_name":"Mouse muscle mitochondrial pyruvate dehydrogenase activity","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"3e839b9f-7bb3-55f3-b10e-0564dfe2ce24","stable_key":"6cdb37aa-8998-5ea8-829d-4f995caf98fc:l-carnitine-crat-pdh-event","event_type":"observed_relationship","label":"Carnitine needs the acetyl-transfer enzyme to relieve this brake on glucose oxidation.","description":"Adding carnitine stimulated PDH activity 1.8-fold in control muscle mitochondria but did not stimulate it in Crat-null mitochondria.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"6e34c035-9371-578f-b799-fd2a14e9e40f","slug":"l-carnitine","display_name":"L-Carnitine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"d8a37877-cf9f-5fd1-8695-3d82ef6868ab","slug":"mouse-muscle-pdh-activity","display_name":"Mouse muscle mitochondrial pyruvate dehydrogenase activity","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"224eacc1-fea4-5737-b661-56e7e41a64e7","slug":"mouse-crat","display_name":"Mouse carnitine acetyltransferase / Crat","entity_type_key":"protein"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"b7ed6e4c-e560-5cee-b68f-895f21862e6f","slug":"acetyl-coa","display_name":"Acetyl-CoA","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"4faa6456-aff8-59eb-9e3f-3326a436e401","slug":"coenzyme-a","display_name":"Coenzyme A","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"a53bcb40-1c97-5845-a48f-6ae54b9867ac","slug":"mouse-pdh-complex","display_name":"Mouse pyruvate dehydrogenase complex","entity_type_key":"protein_complex"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary full-text Figure 4","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Isolated mouse muscle mitochondria; pyruvate-only respiratory context and direct PDH assay.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"The effect is context-dependent; liver mitochondria also lacked the stimulation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Carnitine collection; isomer, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-carnitine","display_name":"L-Carnitine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Carnitine needs the acetyl-transfer enzyme to relieve this brake on glucose oxidation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Muscle-specific deletion of carnitine acetyltransferase compromises glucose tolerance and metabolic flexibility. · 2012 · https://pubmed.ncbi.nlm.nih.gov/22560225/ · DOI 10.1016/j.cmet.2012.04.005","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"9fa10239-7e29-5568-afc2-9aa7880f68e9","evidence_kind":"source_excerpt","locator":"Lines 162-168","start_line":162,"end_line":168,"excerpt":"## l-carnitine-crat-pdh\nCarnitine needs the acetyl-transfer enzyme to relieve this brake on glucose oxidation.\nAdding carnitine stimulated PDH activity 1.8-fold in control muscle mitochondria but did not stimulate it in Crat-null mitochondria.\nModel: Isolated mouse muscle mitochondria; pyruvate-only respiratory context and direct PDH assay.\nLimitations: The effect is context-dependent; liver mitochondria also lacked the stimulation.\nEvidence access: Primary full-text Figure 4\nMuscle-specific deletion of carnitine acetyltransferase compromises glucose tolerance and metabolic flexibility. · 2012 · https://pubmed.ncbi.nlm.nih.gov/22560225/ · DOI 10.1016/j.cmet.2012.04.005","model_system":"Isolated mouse muscle mitochondria; pyruvate-only respiratory context and direct PDH assay.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"e2c9c42b-806a-55e2-abde-b0320ea94704","stable_key":"import-6cdb37aa-8998-5ea8-829d-4f995caf98fc","title":"L-Carnitine: synthesis, acyl-group transport, fuel selection and nutrient interactions (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; 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