{"id":"7f55ff13-5582-5b64-b03a-5ae000ff40e7","stable_key":"a8baf7e9-80e4-5d8c-adec-9a63e84d2f21:l-cysteine-methionine-sparing-limit","predicate":"does_not_change_detectably","statement":"In eight healthy adults, adding 6.5 mg/kg/day cystine to a diet containing 5 mg/kg/day methionine did not significantly change methionine oxidation compared with the same low-methionine diet without cystine.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"neutral","is_public":true,"mechanism_event_id":"8cd72aac-73bc-54ad-94d1-9ea57c144ff0","mechanism_event_label":"A plausible nutrient-saving relationship was not detectable with this particular short-term measurement.","subject":{"id":"cdd84f4d-3e8f-502a-a8c5-19672cc5346f","slug":"cystine","display_name":"Cystine","entity_type_key":"small_molecule"},"object":{"id":"335c87b9-5c4a-56b9-97a5-6a0000d298dc","slug":"human-fed-methionine-oxidation-cystine-study","display_name":"Fed methionine oxidation in the 1997 cystine-intake study","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"8cd72aac-73bc-54ad-94d1-9ea57c144ff0","stable_key":"a8baf7e9-80e4-5d8c-adec-9a63e84d2f21:l-cysteine-methionine-sparing-limit-event","event_type":"observed_relationship","label":"A plausible nutrient-saving relationship was not detectable with this particular short-term measurement.","description":"In eight healthy adults, adding 6.5 mg/kg/day cystine to a diet containing 5 mg/kg/day methionine did not significantly change methionine oxidation compared with the same low-methionine diet without cystine.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"cdd84f4d-3e8f-502a-a8c5-19672cc5346f","slug":"cystine","display_name":"Cystine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"335c87b9-5c4a-56b9-97a5-6a0000d298dc","slug":"human-fed-methionine-oxidation-cystine-study","display_name":"Fed methionine oxidation in the 1997 cystine-intake study","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"ca899f13-50ad-55e5-ab99-329ae0038c74","slug":"l-cysteine","display_name":"L-Cysteine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"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":3,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Six-day dietary periods followed by oral tracers and fasting/fed measurements on day seven.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This endpoint and regimen do not disprove every methionine-sparing effect or define current intake recommendations.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Cysteine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-cysteine","display_name":"L-Cysteine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"A plausible nutrient-saving relationship was not detectable with this particular short-term measurement.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Effect of cystine intake on methionine kinetics and oxidation determined with oral tracers of methionine and cysteine in healthy adults. · 1997 · https://pubmed.ncbi.nlm.nih.gov/9250106/ · DOI 10.1093/ajcn/66.2.283","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"9c6ee75f-c10b-5c4d-bd50-3d9ec36a7bf2","evidence_kind":"source_excerpt","locator":"Lines 444-450","start_line":444,"end_line":450,"excerpt":"## l-cysteine-methionine-sparing-limit\nA plausible nutrient-saving relationship was not detectable with this particular short-term measurement.\nIn eight healthy adults, adding 6.5 mg/kg/day cystine to a diet containing 5 mg/kg/day methionine did not significantly change methionine oxidation compared with the same low-methionine diet without cystine.\nModel: Six-day dietary periods followed by oral tracers and fasting/fed measurements on day seven.\nLimitations: This endpoint and regimen do not disprove every methionine-sparing effect or define current intake recommendations.\nEvidence access: Primary abstract\nEffect of cystine intake on methionine kinetics and oxidation determined with oral tracers of methionine and cysteine in healthy adults. · 1997 · https://pubmed.ncbi.nlm.nih.gov/9250106/ · DOI 10.1093/ajcn/66.2.283","model_system":"Six-day dietary periods followed by oral tracers and fasting/fed measurements on day seven.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; 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