{"id":"035cbcb7-3fc2-5fdf-879c-678298fe9ce5","stable_key":"31b1baa4-4113-5541-b9e7-fe44a5253a07:oxidized-fmn-null","predicate":"forms_nonproductive_complex_with","statement":"An oxidized-FMN/EPSP/enzyme complex formed without productive chorismate-synthase turnover.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"49b25aff-9a12-5101-84c4-5fdbe0067783","mechanism_event_label":"An oxidized-FMN/EPSP/enzyme complex formed without productive chorismate-synthase turnover.","subject":{"id":"d3eacf85-1a35-546d-bd30-161474dd9691","slug":"fmn","display_name":"Flavin mononucleotide","entity_type_key":"small_molecule"},"object":{"id":"c8d1c271-dd44-5865-ae28-e4de9e5db241","slug":"ecoli-aroc","display_name":"Escherichia coli chorismate synthase / AroC","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"49b25aff-9a12-5101-84c4-5fdbe0067783","stable_key":"31b1baa4-4113-5541-b9e7-fe44a5253a07:oxidized-fmn-null-event","event_type":"biochemical_relationship","label":"An oxidized-FMN/EPSP/enzyme complex formed without productive chorismate-synthase turnover.","description":"**Chorismate synthase needs reduced FMN.** E. coli AroC converts EPSP to chorismate with phosphate elimination. Reduced FMN is required although the overall substrate conversion is not a net redox reaction; flavin is a catalytic cofactor rather than a stoichiometrically consumed vitamin. The 1998 study observed a stable oxidized-FMN/EPSP/enzyme complex without productive turnover. Binding, cofactor quantity and cofactor redox state therefore answer different questions. In Neurospora crassa, bifunctional chorismate synthase can use NADPH to reduce its flavin; that reductase capability must not be assigned to every bacterial AroC. [Evidence for a major structural change in Escherichia coli chorismate synthase induced by flavin and substrate binding.](https://pubmed.ncbi.nlm.nih.gov/9761730/) [Mechanism of chorismate synthase. Role of the two invariant histidine residues in the active site.](https://pubmed.ncbi.nlm.nih.gov/14668332/)","status":"provisional","compartment":null,"participants":[{"entity":{"id":"d3eacf85-1a35-546d-bd30-161474dd9691","slug":"fmn","display_name":"Flavin mononucleotide","entity_type_key":"small_molecule"},"role":"tested factor","stoichiometry":null,"state_label":"Oxidized FMN plus EPSP and enzyme","sequence_order":0,"notes":""},{"entity":{"id":"c8d1c271-dd44-5865-ae28-e4de9e5db241","slug":"ecoli-aroc","display_name":"Escherichia coli chorismate synthase / AroC","entity_type_key":"protein"},"role":"measured outcome","stoichiometry":null,"state_label":"no_detected_change","sequence_order":1,"notes":""},{"entity":{"id":"e27b2697-e6fe-59a6-ace0-69924b289e20","slug":"epsp","display_name":"5-Enolpyruvylshikimate 3-phosphate / EPSP","entity_type_key":"small_molecule"},"role":"substrate bound in nonproductive complex","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"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":"E. coli ternary-complex experiment.","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":"Null denotes no productive turnover in the oxidized complex, not equal activity versus reduced FMN; binding and catalysis are distinct.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"An oxidized-FMN/EPSP/enzyme complex formed without productive chorismate-synthase turnover.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Evidence for a major structural change in Escherichia coli chorismate synthase induced by flavin and substrate binding. | 1998 | DOI 10.1042/bj3350319 | PMID 9761730 | https://pubmed.ncbi.nlm.nih.gov/9761730/ | https://doi.org/10.1042/bj3350319 | https://pmc.ncbi.nlm.nih.gov/articles/PMC1219785/","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Mechanism of chorismate synthase. Role of the two invariant histidine residues in the active site. | 2004 | DOI 10.1074/jbc.m312471200 | PMID 14668332 | https://pubmed.ncbi.nlm.nih.gov/14668332/ | https://doi.org/10.1074/jbc.m312471200","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"source_locator","value_text":"Reviewed reference lines 21-21; exact primary location described in quoted passage where extracted.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"85320c40-8a8d-51d0-a6f0-8e49567d4c39","evidence_kind":"source_excerpt","locator":"Lines 21-21","start_line":21,"end_line":21,"excerpt":"**Chorismate synthase needs reduced FMN.** E. coli AroC converts EPSP to chorismate with phosphate elimination. Reduced FMN is required although the overall substrate conversion is not a net redox reaction; flavin is a catalytic cofactor rather than a stoichiometrically consumed vitamin. The 1998 study observed a stable oxidized-FMN/EPSP/enzyme complex without productive turnover. Binding, cofactor quantity and cofactor redox state therefore answer different questions. In Neurospora crassa, bifunctional chorismate synthase can use NADPH to reduce its flavin; that reductase capability must not be assigned to every bacterial AroC. [Evidence for a major structural change in Escherichia coli chorismate synthase induced by flavin and substrate binding.](https://pubmed.ncbi.nlm.nih.gov/9761730/) [Mechanism of chorismate synthase. Role of the two invariant histidine residues in the active site.](https://pubmed.ncbi.nlm.nih.gov/14668332/)","model_system":"E. coli ternary-complex experiment.","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. Not a verbatim quotation from a primary paper.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"e6ae59de-0369-5c2f-8262-57d91302671c","stable_key":"import-31b1baa4-4113-5541-b9e7-fe44a5253a07","title":"Shikimic acid: detailed mechanisms of action (reviewed 5 October 2026)","document_type":"imported_text","citation_label":"Original AI-assisted review of primary studies and, where relevant, official regulatory records. Access level is retained per claim. Corrections, null results and unresolved questions remain explicit. Not publisher full text or independent replication.","file_path":"","sha256":"95b1f9e9577661312d67f36e156d2e49326b207f296c1c0e801a5b007fd8e283","revision_id":"cd3237f1-131a-557d-84b5-7543259807b0","review_status":"unverified_draft","notes":""}}],"relations":[{"id":"9331efa7-3dd3-5d39-9fe9-4a31cf344bb6","relation_type":"qualifies","notes":"Binding with oxidized flavin does not establish productive catalysis.","source_claim_id":"035cbcb7-3fc2-5fdf-879c-678298fe9ce5","source_claim_key":"31b1baa4-4113-5541-b9e7-fe44a5253a07:oxidized-fmn-null","source_statement":"An oxidized-FMN/EPSP/enzyme complex formed without productive chorismate-synthase turnover.","target_claim_id":"d51cb731-e4e2-5b68-b072-21553643a073","target_claim_key":"31b1baa4-4113-5541-b9e7-fe44a5253a07:reduced-fmn-aroc","target_statement":"Reduced FMN supports productive E. coli chorismate-synthase catalysis."}],"conflicts":[],"corrections":[],"research":null}