{"id":"24329cb1-daa5-53a1-b4ca-e827b47a609e","stable_key":"584c58f5-ab9f-53f3-97a9-55783db943b0:tryptophan-indoxyl-sulfation","predicate":"catalyzes_formation","statement":"Recombinant human SULT1A1*2 converted indoxyl to indoxyl sulfate using PAPS; apparent indoxyl Km was 5.6 ± 1.8 micromolar.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"ce16e763-34c8-54f1-92fa-4eae2a6acf09","mechanism_event_label":"A human sulfation enzyme adds a sulfur-containing group to the metabolite.","subject":{"id":"77a2330c-c4ad-59f2-9c0e-67a508bfe20d","slug":"sult1a1","display_name":"Human sulfotransferase 1A1 / SULT1A1","entity_type_key":"protein"},"object":{"id":"6cfa468b-cd28-52fe-bea7-34433868935e","slug":"indoxyl-sulfate","display_name":"Indoxyl sulfate","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"ce16e763-34c8-54f1-92fa-4eae2a6acf09","stable_key":"584c58f5-ab9f-53f3-97a9-55783db943b0:tryptophan-indoxyl-sulfation-event","event_type":"observed_relationship","label":"A human sulfation enzyme adds a sulfur-containing group to the metabolite.","description":"Recombinant human SULT1A1*2 converted indoxyl to indoxyl sulfate using PAPS; apparent indoxyl Km was 5.6 ± 1.8 micromolar.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"77a2330c-c4ad-59f2-9c0e-67a508bfe20d","slug":"sult1a1","display_name":"Human sulfotransferase 1A1 / SULT1A1","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"6cfa468b-cd28-52fe-bea7-34433868935e","slug":"indoxyl-sulfate","display_name":"Indoxyl sulfate","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":"f53f8923-359a-5c38-b601-604497114e8c","slug":"indoxyl","display_name":"Indoxyl / 3-hydroxyindole","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"44432084-b8c5-5d59-a682-6bc790ebbb6d","slug":"paps","display_name":"3-prime-Phosphoadenosine-5-prime-phosphosulfate / PAPS","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human recombinant allozyme and liver cytosol kinetic comparison.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Sulfation does not necessarily make a retained metabolite harmless; no inference that sulfur intake controls clinical toxicity.","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 human sulfation enzyme adds a sulfur-containing group to the metabolite.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Sulfation of indoxyl by human and rat aryl (phenol) sulfotransferases to form indoxyl sulfate. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12064372/ · DOI 10.1007/BF03190428","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"c0818202-f274-5746-85d5-bc17f392ef81","evidence_kind":"source_excerpt","locator":"Lines 594-600","start_line":594,"end_line":600,"excerpt":"## tryptophan-indoxyl-sulfation\nA human sulfation enzyme adds a sulfur-containing group to the metabolite.\nRecombinant human SULT1A1*2 converted indoxyl to indoxyl sulfate using PAPS; apparent indoxyl Km was 5.6 ± 1.8 micromolar.\nModel: Human recombinant allozyme and liver cytosol kinetic comparison.\nLimitations: Sulfation does not necessarily make a retained metabolite harmless; no inference that sulfur intake controls clinical toxicity.\nEvidence access: Primary abstract\nSulfation of indoxyl by human and rat aryl (phenol) sulfotransferases to form indoxyl sulfate. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12064372/ · DOI 10.1007/BF03190428","model_system":"Human recombinant allozyme and liver cytosol kinetic comparison.","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}