{"id":"da57b303-304a-5d06-838e-99412b8ce347","stable_key":"911fb3c7-8cc3-5667-b677-5682fab67648:histidine-sn2-uptake","predicate":"cotransports","statement":"Expressed human SN2 transported histidine with sodium dependence and strong pH sensitivity; the measured histidine Km was 0.6 +/- 0.1 mM.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"536519f3-52fe-558a-854b-d58226ca7943","mechanism_event_label":"A second uptake system depends on the ionic and pH environment.","subject":{"id":"0df8485b-d5ef-5e09-b797-a953b46dd52d","slug":"slc38a5","display_name":"Human system N transporter SN2 / SLC38A5","entity_type_key":"protein"},"object":{"id":"44374451-3436-5136-a8ae-5dcc6d8c353b","slug":"histidine","display_name":"L-Histidine","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"536519f3-52fe-558a-854b-d58226ca7943","stable_key":"911fb3c7-8cc3-5667-b677-5682fab67648:histidine-sn2-uptake-event","event_type":"observed_relationship","label":"A second uptake system depends on the ionic and pH environment.","description":"Expressed human SN2 transported histidine with sodium dependence and strong pH sensitivity; the measured histidine Km was 0.6 +/- 0.1 mM.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"0df8485b-d5ef-5e09-b797-a953b46dd52d","slug":"slc38a5","display_name":"Human system N transporter SN2 / SLC38A5","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"44374451-3436-5136-a8ae-5dcc6d8c353b","slug":"histidine","display_name":"L-Histidine","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"38de8704-84db-5770-ac1d-242cd787e798","slug":"sodium-ion","display_name":"Sodium ion","entity_type_key":"ion"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"8637bb39-2c30-5168-baaf-3e613d831db0","slug":"glutamine","display_name":"L-Glutamine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"22df3254-9178-50c5-899c-d004c1316ab0","slug":"l-asparagine","display_name":"L-Asparagine","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":"Cloned human liver-cell SN2 in mammalian expression assays.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Transporter kinetics do not supply a dietary sodium or histidine target.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Histidine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"histidine","display_name":"L-Histidine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"A second uptake system depends on the ionic and pH environment.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Structure, function, and tissue expression pattern of human SN2, a subtype of the amino acid transport system N. · 2001 · https://pubmed.ncbi.nlm.nih.gov/11243884/ · DOI 10.1006/bbrc.2001.4504","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"transport_effect","value_text":"raises","comparator":null,"unit":null,"notes":"Sodium-dependent histidine transport with a measured Km of 0.6 mM.","entity":null},{"dimension":"transport_pool","value_text":"the expressing cell","comparator":null,"unit":null,"notes":"Sodium-dependent histidine transport with a measured Km of 0.6 mM.","entity":null}],"evidence":[{"id":"52e012ca-4062-5bda-a3e6-e360f24894fc","evidence_kind":"source_excerpt","locator":"Lines 74-80","start_line":74,"end_line":80,"excerpt":"## histidine-sn2-uptake\nA second uptake system depends on the ionic and pH environment.\nExpressed human SN2 transported histidine with sodium dependence and strong pH sensitivity; the measured histidine Km was 0.6 +/- 0.1 mM.\nModel: Cloned human liver-cell SN2 in mammalian expression assays.\nLimitations: Transporter kinetics do not supply a dietary sodium or histidine target.\nEvidence access: Primary abstract\nStructure, function, and tissue expression pattern of human SN2, a subtype of the amino acid transport system N. · 2001 · https://pubmed.ncbi.nlm.nih.gov/11243884/ · DOI 10.1006/bbrc.2001.4504","model_system":"Cloned human liver-cell SN2 in mammalian expression assays.","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":"ce59e6c9-1213-523b-9d0b-400b7a81cd1c","stable_key":"import-911fb3c7-8cc3-5667-b677-5682fab67648","title":"L-Histidine: supply, catabolism, histamine, receptors and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. 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