{"id":"276b86a7-1bc0-5477-849e-1f5d34c9a79e","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-transport-pdxp-magnesium","predicate":"activates","statement":"Human erythrocyte pyridoxal phosphatase required divalent cations; magnesium activated PLP hydrolysis with Michaelis-Menten behavior.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"983e49b4-0bdb-5a53-a4b0-282ee4f5a157","mechanism_event_label":"Magnesium supports B6 dephosphorylation as well as activation.","subject":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"object":{"id":"a0d74853-72b7-546d-a7c7-d37602ba990a","slug":"pdxp","display_name":"Human pyridoxal phosphatase / PDXP","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"983e49b4-0bdb-5a53-a4b0-282ee4f5a157","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-transport-pdxp-magnesium-event","event_type":"biochemical_relationship","label":"Magnesium supports B6 dephosphorylation as well as activation.","description":"Human erythrocyte pyridoxal phosphatase required divalent cations; magnesium activated PLP hydrolysis with Michaelis-Menten behavior.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"6b656ff5-9532-5da4-8eea-8ca163a48649","slug":"pyridoxal-phosphate","display_name":"PLP","entity_type_key":"small_molecule"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"9bf6269d-9e01-553d-bd8b-11a0d613bfca","slug":"pyridoxal","display_name":"Pyridoxal","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"a0d74853-72b7-546d-a7c7-d37602ba990a","slug":"pdxp","display_name":"Human pyridoxal phosphatase / PDXP","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"Magnesium participates in both sides of B6 phosphate cycling.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_location","value_text":"Indexed abstract: divalent-cation kinetics at pH 7.4, 37 C","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified human erythrocyte pyridoxal phosphatase kinetics.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"pH 7.4, 37 C; Mg2+ titration.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Other metals also activated in vitro; does not establish net PLP response to changing dietary magnesium.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-b6","display_name":"Vitamin B6","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Magnesium supports B6 dephosphorylation as well as activation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[fonda1995] Kinetic mechanism and divalent metal activation of human erythrocyte pyridoxal phosphatase. (1995). https://pubmed.ncbi.nlm.nih.gov/7625842/ DOI: 10.1016/0003-9861(95)90018-7","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Erythrocyte enzyme","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"0395e57d-483a-507a-bcad-ff27bc9b5707","evidence_kind":"source_excerpt","locator":"Lines 282-294","start_line":282,"end_line":294,"excerpt":"### b6-transport-pdxp-magnesium\nHuman erythrocyte pyridoxal phosphatase required divalent cations; magnesium activated PLP hydrolysis with Michaelis-Menten behavior.\nCondition category: normal\nnutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Magnesium supports B6 dephosphorylation as well as activation.\norganism: Homo sapiens\ntissue_or_cell_type: Erythrocyte enzyme\nexperimental_model: Purified human erythrocyte pyridoxal phosphatase kinetics.\nlimitations: Other metals also activated in vitro; does not establish net PLP response to changing dietary magnesium.\nexposure: pH 7.4, 37 C; Mg2+ titration.\nevidence_location: Indexed abstract: divalent-cation kinetics at pH 7.4, 37 C\ncross_nutrient: Magnesium participates in both sides of B6 phosphate cycling.\n[fonda1995] Kinetic mechanism and divalent metal activation of human erythrocyte pyridoxal phosphatase. (1995). https://pubmed.ncbi.nlm.nih.gov/7625842/ DOI: 10.1016/0003-9861(95)90018-7","model_system":"Purified human erythrocyte pyridoxal phosphatase kinetics.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [fonda1995] Kinetic mechanism and divalent metal activation of human erythrocyte pyridoxal phosphatase. (1995). https://pubmed.ncbi.nlm.nih.gov/7625842/ DOI: 10.1016/0003-9861(95)90018-7","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"251773bb-16f5-5903-b135-db4a61d9dec4","stable_key":"import-1310afbd-6010-586e-805d-551d846da421","title":"Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"ef0019b344b2219220f801a84d0d138ff6880c1be1a59540d9034bfa4334f61e","revision_id":"cac3555f-48af-5c52-a84e-add4482c87fb","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}