{"id":"a3118006-7591-52a7-953f-ebc5ec345e82","stable_key":"fd37d270-3395-56d6-9f1c-ddda56e606f6:arg-nos-second","predicate":"converted_to","statement":"The second oxygenation yielded NO and citrulline and required added NADPH and calcium/calmodulin.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"4252b20a-3526-56c4-ac4c-f71dc7754224","mechanism_event_label":"The next reaction produces the signal and recycles the carbon skeleton.","subject":{"id":"bd5e3f2f-ae07-5ae7-97d5-c93dbec2dfba","slug":"n-hydroxy-l-arginine","display_name":"Nω-Hydroxy-L-arginine","entity_type_key":"small_molecule"},"object":{"id":"f2a6b7ab-ad41-5ada-8895-41d6ce42f4e4","slug":"nitric-oxide","display_name":"NO","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"4252b20a-3526-56c4-ac4c-f71dc7754224","stable_key":"fd37d270-3395-56d6-9f1c-ddda56e606f6:arg-nos-second-event","event_type":"observed_relationship","label":"The next reaction produces the signal and recycles the carbon skeleton.","description":"The second oxygenation yielded NO and citrulline and required added NADPH and calcium/calmodulin.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"bd5e3f2f-ae07-5ae7-97d5-c93dbec2dfba","slug":"n-hydroxy-l-arginine","display_name":"Nω-Hydroxy-L-arginine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"f2a6b7ab-ad41-5ada-8895-41d6ce42f4e4","slug":"nitric-oxide","display_name":"NO","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"370422f0-f4b9-517d-96f7-d385bbe043db","slug":"rat-nos1","display_name":"Rat neuronal nitric oxide synthase / Nos1","entity_type_key":"protein"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"f53c7bfb-3b91-56fe-bebd-28623cfe13a0","slug":"citrulline","display_name":"L-Citrulline","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"4aba2a5e-8d06-5304-bb01-c0402b225a94","slug":"nadph","display_name":"NADPH","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"a79ecb55-2003-5544-9599-c2136624394a","slug":"calcium-calmodulin","display_name":"Calcium/calmodulin","entity_type_key":"protein_complex"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""},{"entity":{"id":"899c7ab0-6f81-5b38-a6bd-fbb33d66ac8d","slug":"oxygen","display_name":"Molecular oxygen","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":6,"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":"Purified preparation; residual enzyme reductant supported a limited first reaction without added NADPH. This does not imply physiological NOS is NADPH independent.","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":"The next reaction produces the signal and recycles the carbon skeleton.","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":"3218e3e4-10d4-5bf0-af17-888c6ec2c7da","evidence_kind":"source_excerpt","locator":"Lines 78-84","start_line":78,"end_line":84,"excerpt":"## arg-nos-second\nThe next reaction produces the signal and recycles the carbon skeleton.\nThe second oxygenation yielded NO and citrulline and required added NADPH and calcium/calmodulin.\nModel: Rat cerebellar NOS preparation; separated partial reactions.\nLimitations: Purified preparation; residual enzyme reductant supported a limited first reaction without added NADPH. This does not imply physiological NOS is NADPH independent.\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. 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