{"id":"a128ab06-905c-5b46-b1dc-82e3d63ad5c6","stable_key":"31b1baa4-4113-5541-b9e7-fe44a5253a07:pabc-paba","predicate":"converted_to_in_recorded_reaction","statement":"PLP-containing PabC cleaves aminodeoxychorismate to pABA and pyruvate.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"072fa6e4-e0d7-5cd7-bca8-cd922b85aa26","mechanism_event_label":"PLP-containing PabC cleaves aminodeoxychorismate to pABA and pyruvate.","subject":{"id":"1e1ed94a-1c72-5ae7-a9c8-021fe5e8e4c5","slug":"4-amino-4-deoxychorismate","display_name":"4-Amino-4-deoxychorismate","entity_type_key":"small_molecule"},"object":{"id":"eef4779e-36ce-504c-be2c-a72bdb64f22d","slug":"4-aminobenzoate","display_name":"4-Aminobenzoate / pABA","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"072fa6e4-e0d7-5cd7-bca8-cd922b85aa26","stable_key":"31b1baa4-4113-5541-b9e7-fe44a5253a07:pabc-paba-event","event_type":"biochemical_reaction","label":"PLP-containing PabC cleaves aminodeoxychorismate to pABA and pyruvate.","description":"**The folate branch contains a B6-dependent step.** In E. coli, PabA supplies nitrogen from glutamine, generating glutamate; PabB uses chorismate and that nitrogen to form 4-amino-4-deoxychorismate. PabC then cleaves this intermediate to p-aminobenzoate (pABA) and pyruvate. The purified PabC enzyme contains pyridoxal phosphate (PLP), a B6 cofactor. A disrupted pabC strain required external pABA for growth. This establishes a microbial cofactor and biosynthetic dependency, not that marginal human B6 deficiency causes microbial folate failure. pABA is a precursor used in bacterial folate synthesis, not folate itself. [para-aminobenzoate synthesis from chorismate occurs in two steps.](https://pubmed.ncbi.nlm.nih.gov/2656685/) [Characterization and sequence of Escherichia coli pabC, the gene encoding aminodeoxychorismate lyase, a pyridoxal phosphate-containing enzyme.](https://pubmed.ncbi.nlm.nih.gov/1644759/)","status":"provisional","compartment":null,"participants":[{"entity":{"id":"1e1ed94a-1c72-5ae7-a9c8-021fe5e8e4c5","slug":"4-amino-4-deoxychorismate","display_name":"4-Amino-4-deoxychorismate","entity_type_key":"small_molecule"},"role":"input","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"eef4779e-36ce-504c-be2c-a72bdb64f22d","slug":"4-aminobenzoate","display_name":"4-Aminobenzoate / pABA","entity_type_key":"small_molecule"},"role":"output","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"03b17dae-6284-55ba-a8c1-42f80d104a31","slug":"ecoli-pabc","display_name":"Escherichia coli aminodeoxychorismate lyase / PabC","entity_type_key":"protein"},"role":"catalyst","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"91e6d4f5-fba1-542d-b68a-57cc28e1e425","slug":"pyruvate","display_name":"Pyruvate","entity_type_key":"small_molecule"},"role":"output","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"6b656ff5-9532-5da4-8eea-8ca163a48649","slug":"pyridoxal-phosphate","display_name":"PLP","entity_type_key":"small_molecule"},"role":"cofactor","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary indexed abstract reviewed; full results, tables and supplements not independently extracted.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Escherichia coli biochemical pathway; source-specific enzyme evidence recorded in the passage.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"interpretation_status","value_text":"Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Interpret only within the recorded preparation, exposure and comparator. 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PabC then cleaves this intermediate to p-aminobenzoate (pABA) and pyruvate. The purified PabC enzyme contains pyridoxal phosphate (PLP), a B6 cofactor. A disrupted pabC strain required external pABA for growth. This establishes a microbial cofactor and biosynthetic dependency, not that marginal human B6 deficiency causes microbial folate failure. pABA is a precursor used in bacterial folate synthesis, not folate itself. [para-aminobenzoate synthesis from chorismate occurs in two steps.](https://pubmed.ncbi.nlm.nih.gov/2656685/) [Characterization and sequence of Escherichia coli pabC, the gene encoding aminodeoxychorismate lyase, a pyridoxal phosphate-containing enzyme.](https://pubmed.ncbi.nlm.nih.gov/1644759/)","model_system":"Escherichia coli biochemical pathway; source-specific enzyme evidence recorded in the passage.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Exact excerpt of the retained AI-assisted reviewed reference; primary sources are cited in primary_references and access scope is retained. 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