{"id":"d0b88d00-05e0-57b0-92c0-d11d52163c36","stable_key":"fd37d270-3395-56d6-9f1c-ddda56e606f6:arg-nos-bh4","predicate":"stimulates","statement":"BH4 stimulated both partial reactions; the first increased approximately threefold.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"9891be4e-bf23-5c16-80dd-6c00a791e0ac","mechanism_event_label":"Substrate availability and cofactor availability are separate requirements.","subject":{"id":"1c231b90-c106-507a-8766-870ecb40e368","slug":"tetrahydrobiopterin","display_name":"Tetrahydrobiopterin / BH4","entity_type_key":"small_molecule"},"object":{"id":"370422f0-f4b9-517d-96f7-d385bbe043db","slug":"rat-nos1","display_name":"Rat neuronal nitric oxide synthase / Nos1","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"9891be4e-bf23-5c16-80dd-6c00a791e0ac","stable_key":"fd37d270-3395-56d6-9f1c-ddda56e606f6:arg-nos-bh4-event","event_type":"observed_relationship","label":"Substrate availability and cofactor availability are separate requirements.","description":"BH4 stimulated both partial reactions; the first increased approximately threefold.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"1c231b90-c106-507a-8766-870ecb40e368","slug":"tetrahydrobiopterin","display_name":"Tetrahydrobiopterin / BH4","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"370422f0-f4b9-517d-96f7-d385bbe043db","slug":"rat-nos1","display_name":"Rat neuronal nitric oxide synthase / Nos1","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"eeca3c9e-7749-5677-b7bd-37fe8f7c228d","slug":"arginine","display_name":"L-Arginine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"bd5e3f2f-ae07-5ae7-97d5-c93dbec2dfba","slug":"n-hydroxy-l-arginine","display_name":"Nω-Hydroxy-L-arginine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Rat cerebellar NOS preparation; separated partial reactions.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Assay-specific stimulation, not a dietary BH4 or arginine treatment rule.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Arginine collection; tissue, species, dose and formulation distinctions retained.","comparator":null,"unit":null,"notes":"","entity":{"slug":"arginine","display_name":"L-Arginine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Substrate availability and cofactor availability are separate requirements.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Characteristics of the nitric oxide synthase-catalyzed conversion of arginine to N-hydroxyarginine, the first oxygenation step in the enzymic synthesis of nitric oxide. · 1995 · https://pubmed.ncbi.nlm.nih.gov/7530247/ · DOI 10.1074/jbc.270.4.1721","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"836923c1-bfff-5cd5-89ea-440c4ec51ef5","evidence_kind":"source_excerpt","locator":"Lines 86-92","start_line":86,"end_line":92,"excerpt":"## arg-nos-bh4\nSubstrate availability and cofactor availability are separate requirements.\nBH4 stimulated both partial reactions; the first increased approximately threefold.\nModel: Rat cerebellar NOS preparation; separated partial reactions.\nLimitations: Assay-specific stimulation, not a dietary BH4 or arginine treatment rule.\nEvidence access: Primary abstract\nCharacteristics of the nitric oxide synthase-catalyzed conversion of arginine to N-hydroxyarginine, the first oxygenation step in the enzymic synthesis of nitric oxide. · 1995 · https://pubmed.ncbi.nlm.nih.gov/7530247/ · DOI 10.1074/jbc.270.4.1721","model_system":"Rat cerebellar NOS preparation; separated partial reactions.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; primary evidence access stated per claim.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"bb9a67ea-904f-5b8a-93a4-459081212bdd","stable_key":"import-fd37d270-3395-56d6-9f1c-ddda56e606f6","title":"L-Arginine: transport, metabolic branches, nutrient interactions, availability and discovery questions (2026-09-18)","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":"ec0e9a3fb72b7485534e4372a074ac7624a399ff962e55690eb462217b5149ec","revision_id":"af027270-5535-51ae-85ff-9c76c518c962","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}