{"id":"927301a4-f922-51f7-bfbf-b7885b148a58","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-fed-cystathionine-synthesis","predicate":"restriction_increased_fractional_synthesis","statement":"Cystathionine fractional synthesis increased by a mean 12% in eight of nine participants; plasma concentration rose 142 to 236 nmol/L.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"99c3156e-52c7-5b6c-b14a-5d8c9b831ac2","mechanism_event_label":"A faster fractional rate for an intermediate can coexist with preserved overall pathway throughput.","subject":{"id":"c0beb226-8842-501f-a147-cac0d9fa7060","slug":"vitamin-b6","display_name":"Vitamin B6","entity_type_key":"chemical_species"},"object":{"id":"5f64c12d-7f6f-5149-bcff-db2c106e8a4b","slug":"cystathionine-fractional-synthesis-rate","display_name":"Cystathionine fractional synthesis rate","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"99c3156e-52c7-5b6c-b14a-5d8c9b831ac2","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-fed-cystathionine-synthesis-event","event_type":"observed_intervention","label":"A faster fractional rate for an intermediate can coexist with preserved overall pathway throughput.","description":"Cystathionine fractional synthesis increased by a mean 12% in eight of nine participants; 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unverified.","entity":null}],"evidence":[{"id":"1c8a9794-5693-51e7-852f-470e8829dc5e","evidence_kind":"source_excerpt","locator":"Lines 1385-1395","start_line":1385,"end_line":1395,"excerpt":"### b6-fed-cystathionine-synthesis\nCystathionine fractional synthesis increased by a mean 12% in eight of nine participants; plasma concentration rose 142 to 236 nmol/L.\nCondition category: nutrient_deficiency\nnutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A faster fractional rate for an intermediate can coexist with preserved overall pathway throughput.\norganism: Homo sapiens\ntissue_or_cell_type: Human blood and whole-body measurements\nexperimental_model: Nine healthy adults (five women, four men; ages 20–35), repeated postprandial isotope kinetics.\nlimitations: Fractional synthesis, pool size and total flux are distinct measurements.\nexposure: 28 days dietary B6 restriction; plasma PLP49±4 to 19±2 nmol/L.\n[b6-lamers2011] Moderate vitamin B-6 restriction does not alter postprandial methionine cycle rates of remethylation, transmethylation, and total transsulfuration but increases the fractional synthesis rate of cystathionine in healthy young men and women (2011). https://pubmed.ncbi.nlm.nih.gov/21430249/ DOI: 10.3945/jn.110.134197","model_system":"Nine healthy adults (five women, four men; 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Study references: [b6-lamers2011] Moderate vitamin B-6 restriction does not alter postprandial methionine cycle rates of remethylation, transmethylation, and total transsulfuration but increases the fractional synthesis rate of cystathionine in healthy young men and women (2011). https://pubmed.ncbi.nlm.nih.gov/21430249/ DOI: 10.3945/jn.110.134197","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. 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