{"id":"4659a50b-29e9-5119-9b91-ac83384eb1c9","stable_key":"649e861b-265a-5912-bc36-3a73e53ef892:l-serine-psph-physiology","predicate":"is_near_saturated_by","statement":"The 2024 human PSPH study found near-saturation with Mg2+ under physiological conditions and judged ordinary Mg2+/Ca2+ fluctuations unlikely to regulate activity substantially.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"b9ad319d-8381-529b-9a82-c49e23594a42","mechanism_event_label":"A required mineral need not be the rate-limiting input when its binding site is already occupied.","subject":{"id":"1177919d-d7f4-5272-b40c-444f5dbee4d2","slug":"psph","display_name":"Human phosphoserine phosphatase / PSPH","entity_type_key":"protein"},"object":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"evidence_count":1,"mechanism_event":{"id":"b9ad319d-8381-529b-9a82-c49e23594a42","stable_key":"649e861b-265a-5912-bc36-3a73e53ef892:l-serine-psph-physiology-event","event_type":"observed_relationship","label":"A required mineral need not be the rate-limiting input when its binding site is already occupied.","description":"The 2024 human PSPH study found near-saturation with Mg2+ under physiological conditions and judged ordinary Mg2+/Ca2+ fluctuations unlikely to regulate activity substantially.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"1177919d-d7f4-5272-b40c-444f5dbee4d2","slug":"psph","display_name":"Human phosphoserine phosphatase / PSPH","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"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":"e359bc15-e675-5d83-b0fe-1d70814e130b","slug":"calcium-ion","display_name":"Calcium ion","entity_type_key":"ion"},"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":"Purified human wild-type and variant PSPH; kinetic interpretation of physiological ion ranges.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This qualifies physiological extrapolation from binding assays; it does not deny the earlier calcium-bound structure.","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":"A required mineral need not be the rate-limiting input when its binding site is already occupied.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Effect of l-serine and magnesium ions on the functional properties of human phosphoserine phosphatase and its pathogenetic variants. · 2024 · https://pubmed.ncbi.nlm.nih.gov/38278334/ · DOI 10.1016/j.bbadis.2024.167034","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"31cdebbf-2943-5d61-88a9-a10d2b1cabd1","evidence_kind":"source_excerpt","locator":"Lines 62-68","start_line":62,"end_line":68,"excerpt":"## l-serine-psph-physiology\nA required mineral need not be the rate-limiting input when its binding site is already occupied.\nThe 2024 human PSPH study found near-saturation with Mg2+ under physiological conditions and judged ordinary Mg2+/Ca2+ fluctuations unlikely to regulate activity substantially.\nModel: Purified human wild-type and variant PSPH; kinetic interpretation of physiological ion ranges.\nLimitations: This qualifies physiological extrapolation from binding assays; it does not deny the earlier calcium-bound structure.\nEvidence access: Primary abstract\nEffect of l-serine and magnesium ions on the functional properties of human phosphoserine phosphatase and its pathogenetic variants. · 2024 · https://pubmed.ncbi.nlm.nih.gov/38278334/ · DOI 10.1016/j.bbadis.2024.167034","model_system":"Purified human wild-type and variant PSPH; kinetic interpretation of physiological ion ranges.","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}