{"id":"12e20854-61e2-5f76-9836-ae6695fdafb8","stable_key":"08ce9896-9d1c-5bbf-b705-5bfe771091d5:b7-cpt1b-delta28","predicate":"loses_sensitivity_to","statement":"Deleting the first 28 residues of human CPT1B removed high-affinity malonyl-CoA binding and inhibition despite retained catalytic activity.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"bcffc445-9ba2-504a-89a8-f1b97e09d61f","mechanism_event_label":"This engineered change separates the enzyme brake from its basic catalytic function.","subject":{"id":"ac393d42-ce44-514c-bf5f-e02eaaf8987d","slug":"cpt1b-delta28","display_name":"Human CPT1B N-terminal 28-residue deletion","entity_type_key":"protein_state"},"object":{"id":"52c778e0-2b9e-5ce2-8056-a0ffdd726693","slug":"malonyl-coa","display_name":"Malonyl-CoA","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"bcffc445-9ba2-504a-89a8-f1b97e09d61f","stable_key":"08ce9896-9d1c-5bbf-b705-5bfe771091d5:b7-cpt1b-delta28-event","event_type":"biochemical_relationship","label":"This engineered change separates the enzyme brake from its basic catalytic function.","description":"Deleting the first 28 residues of human CPT1B removed high-affinity malonyl-CoA binding and inhibition despite retained catalytic activity.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"d9014bdd-3720-5748-9606-f8a55bbc8bc2","slug":"cpt1b","display_name":"Human carnitine palmitoyltransferase 1B / CPT1B","entity_type_key":"protein"},"role":"wild-type comparator","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"ac393d42-ce44-514c-bf5f-e02eaaf8987d","slug":"cpt1b-delta28","display_name":"Human CPT1B N-terminal 28-residue deletion","entity_type_key":"protein_state"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"52c778e0-2b9e-5ce2-8056-a0ffdd726693","slug":"malonyl-coa","display_name":"Malonyl-CoA","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/biotin-research/10651636.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"e99728ef83700f17a810421385b71ea243576419df807dc4749b588beb01d400\", \"start_char\": 0, \"end_char\": 1542, \"text_sha256\": \"e99728ef83700f17a810421385b71ea243576419df807dc4749b588beb01d400\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human CPT1B wild type and N-terminal deletions expressed in yeast mitochondria","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Malonyl-CoA binding and activity assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Expression host is yeast; these data concern human CPT1B, not every CPT1 isoform or a biotin supplementation outcome.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Biotin research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"biotin","display_name":"Biotin","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"This engineered change separates the enzyme brake from its basic catalytic function.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[b7-p10651636] The first 28 N-terminal amino acid residues of human heart muscle carnitine palmitoyltransferase I are essential for malonyl CoA sensitivity and high-affinity binding. (2000). https://pubmed.ncbi.nlm.nih.gov/10651636/ DOI: 10.1021/bi9918700","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Recombinant human muscle/heart CPT1B","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"76cf2016-5959-54d4-ba16-d8610414ec9d","evidence_kind":"source_excerpt","locator":"Lines 754-765","start_line":754,"end_line":765,"excerpt":"### b7-cpt1b-delta28\nDeleting the first 28 residues of human CPT1B removed high-affinity malonyl-CoA binding and inhibition despite retained catalytic activity.\nCondition category: normal\nnutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: This engineered change separates the enzyme brake from its basic catalytic function.\norganism: Homo sapiens\ntissue_or_cell_type: Recombinant human muscle/heart CPT1B\nexperimental_model: Human CPT1B wild type and N-terminal deletions expressed in yeast mitochondria\nlimitations: Expression host is yeast; these data concern human CPT1B, not every CPT1 isoform or a biotin supplementation outcome.\nexposure: Malonyl-CoA binding and activity assays\nevidence_span: {\"source_cache\": \"artifacts/biotin-research/10651636.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"e99728ef83700f17a810421385b71ea243576419df807dc4749b588beb01d400\", \"start_char\": 0, \"end_char\": 1542, \"text_sha256\": \"e99728ef83700f17a810421385b71ea243576419df807dc4749b588beb01d400\"}\n[b7-p10651636] The first 28 N-terminal amino acid residues of human heart muscle carnitine palmitoyltransferase I are essential for malonyl CoA sensitivity and high-affinity binding. (2000). https://pubmed.ncbi.nlm.nih.gov/10651636/ DOI: 10.1021/bi9918700","model_system":"Human CPT1B wild type and N-terminal deletions expressed in yeast mitochondria","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [b7-p10651636] The first 28 N-terminal amino acid residues of human heart muscle carnitine palmitoyltransferase I are essential for malonyl CoA sensitivity and high-affinity binding. 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