{"id":"4f360197-9cf0-59fc-b439-34382a970299","stable_key":"649e861b-265a-5912-bc36-3a73e53ef892:l-serine-psat-nitrogen","predicate":"transaminates_phosphohydroxypyruvate_to","statement":"Human PSAT1 transfers nitrogen from glutamate to phosphohydroxypyruvate, producing O-phosphoserine and 2-oxoglutarate in a reversible PLP-dependent reaction.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"6957e86f-45cf-5251-bbd2-5b0236fd2aba","mechanism_event_label":"Glutamate supplies nitrogen while active B6 enables the transfer.","subject":{"id":"a549bab7-965e-57f9-99b3-e8dfcb535af5","slug":"psat1","display_name":"Human phosphoserine aminotransferase / PSAT1","entity_type_key":"protein"},"object":{"id":"f8d93623-1546-5bb5-a8a8-55761070bf49","slug":"o-phospho-l-serine","display_name":"O-Phospho-L-serine, free metabolite","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"6957e86f-45cf-5251-bbd2-5b0236fd2aba","stable_key":"649e861b-265a-5912-bc36-3a73e53ef892:l-serine-psat-nitrogen-event","event_type":"observed_relationship","label":"Glutamate supplies nitrogen while active B6 enables the transfer.","description":"Human PSAT1 transfers nitrogen from glutamate to phosphohydroxypyruvate, producing O-phosphoserine and 2-oxoglutarate in a reversible PLP-dependent reaction.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"a549bab7-965e-57f9-99b3-e8dfcb535af5","slug":"psat1","display_name":"Human phosphoserine aminotransferase / PSAT1","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"f8d93623-1546-5bb5-a8a8-55761070bf49","slug":"o-phospho-l-serine","display_name":"O-Phospho-L-serine, free metabolite","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"c882cd0b-9d83-5b07-bd1c-fe4d45657dcb","slug":"l-serine","display_name":"L-Serine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"09de4621-09f2-50d3-b344-8ccdc6b3c467","slug":"3-phosphohydroxypyruvate","display_name":"3-Phosphohydroxypyruvate","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"7da684a4-2641-5bc6-93ae-8c6aa384e487","slug":"glutamate","display_name":"L-Glutamate","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"628ddc2d-e4d9-59c7-ae76-0c0cab80a6b1","slug":"2-oxoglutarate","display_name":"2-Oxoglutarate","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":5,"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":6,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary full text","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human PSAT kinetics and substrate-bound crystal structures.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This is an enzyme reaction, not evidence that dietary glutamate or B6 is limiting in a particular person.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Serine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-serine","display_name":"L-Serine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Glutamate supplies nitrogen while active B6 enables the transfer.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"L-serine biosynthesis in the human central nervous system: Structure and function of phosphoserine aminotransferase. · 2023 · https://pubmed.ncbi.nlm.nih.gov/36851825/ · DOI 10.1002/pro.4609","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"128336bc-8c52-514d-8691-1a4bdc8f53f1","evidence_kind":"source_excerpt","locator":"Lines 30-36","start_line":30,"end_line":36,"excerpt":"## l-serine-psat-nitrogen\nGlutamate supplies nitrogen while active B6 enables the transfer.\nHuman PSAT1 transfers nitrogen from glutamate to phosphohydroxypyruvate, producing O-phosphoserine and 2-oxoglutarate in a reversible PLP-dependent reaction.\nModel: Recombinant human PSAT kinetics and substrate-bound crystal structures.\nLimitations: This is an enzyme reaction, not evidence that dietary glutamate or B6 is limiting in a particular person.\nEvidence access: Primary full text\nL-serine biosynthesis in the human central nervous system: Structure and function of phosphoserine aminotransferase. · 2023 · https://pubmed.ncbi.nlm.nih.gov/36851825/ · DOI 10.1002/pro.4609","model_system":"Recombinant human PSAT kinetics and substrate-bound crystal structures.","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":"70bcf57a-36bb-563f-9073-2d616e5f155a","stable_key":"import-649e861b-265a-5912-bc36-3a73e53ef892","title":"L-Serine: synthesis, one-carbon metabolism, lipids 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. Not publisher full text.","file_path":"","sha256":"22a750ce2b94f8607268c58322c48c4f0468f403b72a4008307538a6e5ff86d5","revision_id":"c1d6a7e1-9558-5bc6-9e3b-7080c26d3dbc","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}