{"id":"26c52c1c-5556-5d7e-91e7-3879fc56a45a","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-fasting-cysteine-flux","predicate":"restriction_did_not_change_measured_turnover","statement":"Whole-body cysteine flux and fractional cystathionine synthesis were unchanged; transsulfuration-derived cysteine synthesis was below detection in this fasting protocol.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"87415e93-3f02-5eb2-8ec4-40e34bb8ad32","mechanism_event_label":"The investigators could measure cysteine turnover but could not reliably quantify one specific input route.","subject":{"id":"c0beb226-8842-501f-a147-cac0d9fa7060","slug":"vitamin-b6","display_name":"Vitamin B6","entity_type_key":"chemical_species"},"object":{"id":"c0b7160c-5e50-5f56-9766-b417fab9647c","slug":"whole-body-cysteine-flux","display_name":"Whole-body cysteine flux","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"87415e93-3f02-5eb2-8ec4-40e34bb8ad32","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-fasting-cysteine-flux-event","event_type":"observed_intervention","label":"The investigators could measure cysteine turnover but could not reliably quantify one specific input route.","description":"Whole-body cysteine flux and fractional cystathionine synthesis were unchanged; 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unverified.","entity":null}],"evidence":[{"id":"994bccc1-5a78-5562-a758-53c478fdb036","evidence_kind":"source_excerpt","locator":"Lines 1334-1344","start_line":1334,"end_line":1344,"excerpt":"### b6-fasting-cysteine-flux\nWhole-body cysteine flux and fractional cystathionine synthesis were unchanged; transsulfuration-derived cysteine synthesis was below detection in this fasting protocol.\nCondition category: nutrient_deficiency\nnutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The investigators could measure cysteine turnover but could not reliably quantify one specific input route.\norganism: Homo sapiens\ntissue_or_cell_type: Human blood and whole-body measurements\nexperimental_model: Nine healthy adults (five women, four men; ages 20–30), controlled restriction with fasting stable-isotope measurements.\nlimitations: Below detection is not zero flux, nor proof that transsulfuration was unchanged.\nexposure: Four weeks below 0.5 mg/day dietary B6; overnight-fasted tracer protocol.\n[b6-davis2006] Plasma glutathione and cystathionine concentrations are elevated but cysteine flux is unchanged by dietary vitamin B-6 restriction in young men and women (2006). https://pubmed.ncbi.nlm.nih.gov/16424114/ DOI: 10.1093/jn/136.2.373","model_system":"Nine healthy adults (five women, four men; ages 20–30), controlled restriction with fasting stable-isotope measurements.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [b6-davis2006] Plasma glutathione and cystathionine concentrations are elevated but cysteine flux is unchanged by dietary vitamin B-6 restriction in young men and women (2006). https://pubmed.ncbi.nlm.nih.gov/16424114/ DOI: 10.1093/jn/136.2.373","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}