{"id":"cde2ed93-1b80-5aff-8d10-2bdcfe2a181f","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-met-transsulfuration-glutathione","predicate":"contributes-sulfur-to","statement":"Tracing in a cultured human hepatoma cell line estimated that transsulfuration supplied homocysteine-derived sulfur to approximately half of the intracellular glutathione pool.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"39e713c1-392d-5b1c-817e-52969a912ab0","mechanism_event_label":"In this cell system, sulfur routed through B6-dependent enzymes helped supply glutathione.","subject":{"id":"5b635b42-bc0d-5c54-aa94-9cf76cd0ed47","slug":"homocysteine","display_name":"Homocysteine","entity_type_key":"small_molecule"},"object":{"id":"b44c9e27-4bbb-52d3-a022-14cddded5073","slug":"glutathione","display_name":"GSH","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"39e713c1-392d-5b1c-817e-52969a912ab0","stable_key":"1310afbd-6010-586e-805d-551d846da421:b6-met-transsulfuration-glutathione-event","event_type":"biochemical_relationship","label":"In this cell system, sulfur routed through B6-dependent enzymes helped supply glutathione.","description":"Tracing in a cultured human hepatoma cell line estimated that transsulfuration supplied homocysteine-derived sulfur to approximately half of the intracellular glutathione pool.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"5b635b42-bc0d-5c54-aa94-9cf76cd0ed47","slug":"homocysteine","display_name":"Homocysteine","entity_type_key":"small_molecule"},"role":"sulfur precursor","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"4688e32c-d7b6-5fca-9eb2-23307c29ae07","slug":"cbs","display_name":"Human cystathionine beta-synthase / CBS","entity_type_key":"protein"},"role":"upstream enzyme","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"4014ee3a-0e44-5379-b541-174aa75bcf90","slug":"cth","display_name":"Human cystathionine gamma-lyase / CTH","entity_type_key":"protein"},"role":"downstream transsulfuration enzyme","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"ca899f13-50ad-55e5-ab99-329ae0038c74","slug":"l-cysteine","display_name":"L-Cysteine","entity_type_key":"small_molecule"},"role":"intermediate","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"b44c9e27-4bbb-52d3-a022-14cddded5073","slug":"glutathione","display_name":"GSH","entity_type_key":"small_molecule"},"role":"downstream product","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"B6-dependent transsulfuration connects methionine/homocysteine to the cysteine supply for glutathione.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Cultured human hepatoma cell line; metabolic sulfur tracing","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Fraction is culture-specific and traces sulfur, not all glutathione atoms; this experiment did not measure dietary B6 depletion.","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":"In this cell system, sulfur routed through B6-dependent enzymes helped supply glutathione.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[b6-glutathione-2000] The quantitatively important relationship between homocysteine metabolism and glutathione synthesis by the transsulfuration pathway and its regulation by redox changes (2000). https://pubmed.ncbi.nlm.nih.gov/11041866/ DOI: 10.1021/bi001088w","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cultured human hepatoma cell line","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"f710f325-e059-57cd-92dc-c511f46114c9","evidence_kind":"source_excerpt","locator":"Lines 590-600","start_line":590,"end_line":600,"excerpt":"### b6-met-transsulfuration-glutathione\nTracing in a cultured human hepatoma cell line estimated that transsulfuration supplied homocysteine-derived sulfur to approximately half of the intracellular glutathione pool.\nCondition category: normal\nnutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: In this cell system, sulfur routed through B6-dependent enzymes helped supply glutathione.\norganism: Homo sapiens\ntissue_or_cell_type: Cultured human hepatoma cell line\nexperimental_model: Cultured human hepatoma cell line; metabolic sulfur tracing\nlimitations: Fraction is culture-specific and traces sulfur, not all glutathione atoms; this experiment did not measure dietary B6 depletion.\ncross_nutrient: B6-dependent transsulfuration connects methionine/homocysteine to the cysteine supply for glutathione.\n[b6-glutathione-2000] The quantitatively important relationship between homocysteine metabolism and glutathione synthesis by the transsulfuration pathway and its regulation by redox changes (2000). https://pubmed.ncbi.nlm.nih.gov/11041866/ DOI: 10.1021/bi001088w","model_system":"Cultured human hepatoma cell line; metabolic sulfur tracing","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [b6-glutathione-2000] The quantitatively important relationship between homocysteine metabolism and glutathione synthesis by the transsulfuration pathway and its regulation by redox changes (2000). https://pubmed.ncbi.nlm.nih.gov/11041866/ DOI: 10.1021/bi001088w","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}