{"id":"d7bd7f0e-c048-5b32-a354-a8f8f5065c6b","stable_key":"584c58f5-ab9f-53f3-97a9-55783db943b0:tryptophan-tnaa-indole","predicate":"converts_to","statement":"Purified E. coli BW25113 TnaA converted L-tryptophan to indole in a PLP-containing assay; tryptophan Km was 0.19 ± 0.009 mM.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"e408cb9a-d82b-5474-a3b6-1d3c06a083de","mechanism_event_label":"A bacterial enzyme creates the indole that can enter host liver metabolism.","subject":{"id":"692b4b36-008c-561a-be81-f953f72c49a4","slug":"e-coli-bw25113-tnaa","display_name":"Escherichia coli BW25113 tryptophanase / TnaA","entity_type_key":"protein"},"object":{"id":"456cd56f-01cb-5202-bb9d-86824e845498","slug":"indole","display_name":"Indole","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"e408cb9a-d82b-5474-a3b6-1d3c06a083de","stable_key":"584c58f5-ab9f-53f3-97a9-55783db943b0:tryptophan-tnaa-indole-event","event_type":"observed_relationship","label":"A bacterial enzyme creates the indole that can enter host liver metabolism.","description":"Purified E. coli BW25113 TnaA converted L-tryptophan to indole in a PLP-containing assay; tryptophan Km was 0.19 ± 0.009 mM.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"692b4b36-008c-561a-be81-f953f72c49a4","slug":"e-coli-bw25113-tnaa","display_name":"Escherichia coli BW25113 tryptophanase / TnaA","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"456cd56f-01cb-5202-bb9d-86824e845498","slug":"indole","display_name":"Indole","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"769339cb-213b-559e-acc0-07ed00368b94","slug":"l-tryptophan","display_name":"L-Tryptophan","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"6b656ff5-9532-5da4-8eea-8ca163a48649","slug":"pyridoxal-phosphate","display_name":"PLP","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary full text, Figure 2 and enzyme-kinetics methods","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified bacterial enzyme kinetics.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Culture kinetics do not predict a person’s production rate.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-tryptophan","display_name":"L-Tryptophan","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"A bacterial enzyme creates the indole that can enter host liver metabolism.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Gut bacteria-derived 5-hydroxyindole is a potent stimulant of intestinal motility via its action on L-type calcium channels. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33481771/ · DOI 10.1371/journal.pbio.3001070","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"537c1d5a-6b30-5200-b2bf-49ba30abdef3","evidence_kind":"source_excerpt","locator":"Lines 634-640","start_line":634,"end_line":640,"excerpt":"## tryptophan-tnaa-indole\nA bacterial enzyme creates the indole that can enter host liver metabolism.\nPurified E. coli BW25113 TnaA converted L-tryptophan to indole in a PLP-containing assay; tryptophan Km was 0.19 ± 0.009 mM.\nModel: Purified bacterial enzyme kinetics.\nLimitations: Culture kinetics do not predict a person’s production rate.\nEvidence access: Primary full text, Figure 2 and enzyme-kinetics methods\nGut bacteria-derived 5-hydroxyindole is a potent stimulant of intestinal motility via its action on L-type calcium channels. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33481771/ · DOI 10.1371/journal.pbio.3001070","model_system":"Purified bacterial enzyme kinetics.","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":"73f9d3e7-fdc9-5418-8f3c-f4ef145f6efa","stable_key":"import-584c58f5-ab9f-53f3-97a9-55783db943b0","title":"Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text.","file_path":"","sha256":"7dfd20063b91900cb5c6ad675e3e675b7e25ef0fb8304eabac6f263cc5518284","revision_id":"bfafd789-fdf5-521f-bd28-c662e01ec1ea","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}