{"id":"3f645242-10a8-5973-841c-465e0d11e26d","stable_key":"41a89233-da9a-5b7b-9c18-e19bbadcfe2d:methionine-mat-potassium","predicate":"coordinates","statement":"An essential potassium ion contacted the beta-phosphoryl oxygen in the human MAT2A catalytic-site ligand structure.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"3e91fbb1-edcc-590b-ba59-379acb459b04","mechanism_event_label":"Potassium participates directly in the enzyme chemistry.","subject":{"id":"5dd31e52-f51e-51f3-880e-240abcc0ab1d","slug":"potassium-ion","display_name":"Potassium ion","entity_type_key":"ion"},"object":{"id":"bbc04455-e242-5f4d-9a6c-5b2ee6a6cb41","slug":"human-mat2a","display_name":"Human methionine adenosyltransferase 2A / MAT2A","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"3e91fbb1-edcc-590b-ba59-379acb459b04","stable_key":"41a89233-da9a-5b7b-9c18-e19bbadcfe2d:methionine-mat-potassium-event","event_type":"observed_relationship","label":"Potassium participates directly in the enzyme chemistry.","description":"An essential potassium ion contacted the beta-phosphoryl oxygen in the human MAT2A catalytic-site ligand structure.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"5dd31e52-f51e-51f3-880e-240abcc0ab1d","slug":"potassium-ion","display_name":"Potassium ion","entity_type_key":"ion"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"bbc04455-e242-5f4d-9a6c-5b2ee6a6cb41","slug":"human-mat2a","display_name":"Human methionine adenosyltransferase 2A / MAT2A","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"9d39f561-740b-5f67-bba7-8a72ef612a99","slug":"methionine","display_name":"L-Methionine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"58b974f1-d389-5bf6-81cd-889c44442c42","slug":"atp","display_name":"ATP","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"825f2da2-01bc-5874-a3c6-64f5ac867db5","slug":"s-adenosylmethionine","display_name":"S-Adenosyl-L-methionine","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":"Purified human MAT2A crystallography and kinetic study.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Does not show that extra potassium increases methylation in potassium-replete humans.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Methionine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"methionine","display_name":"L-Methionine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Potassium participates directly in the enzyme chemistry.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Mechanism and Inhibition of Human Methionine Adenosyltransferase 2A. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33656855/ · DOI 10.1021/acs.biochem.0c00998","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"7e1673d2-731c-566a-bba7-780a63451e41","evidence_kind":"source_excerpt","locator":"Lines 140-146","start_line":140,"end_line":146,"excerpt":"## methionine-mat-potassium\nPotassium participates directly in the enzyme chemistry.\nAn essential potassium ion contacted the beta-phosphoryl oxygen in the human MAT2A catalytic-site ligand structure.\nModel: Purified human MAT2A crystallography and kinetic study.\nLimitations: Does not show that extra potassium increases methylation in potassium-replete humans.\nEvidence access: Primary abstract\nMechanism and Inhibition of Human Methionine Adenosyltransferase 2A. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33656855/ · DOI 10.1021/acs.biochem.0c00998","model_system":"Purified human MAT2A crystallography and kinetic study.","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":"d969b004-ccc2-5bb4-9109-8ac649137ad1","stable_key":"import-41a89233-da9a-5b7b-9c18-e19bbadcfe2d","title":"L-Methionine: transport, methylation, sulfur metabolism 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":"f1c706ef72932eed85df234b6c3304158d503d626a63c69b02a453c162700d26","revision_id":"549035e0-3a72-550a-8a55-e8c5baa51b0d","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}