{"id":"c6f23963-dafc-581d-8bab-b150e3637c1c","stable_key":"db0fc92e-b5ef-5667-a4c5-3ef257edbc9b:glutathione-chac2-gsh","predicate":"degrades","statement":"Purified human CHAC2 degraded reduced GSH with lower catalytic efficiency than CHAC1.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"f6246f65-53a3-50a5-bb83-80d63173f9f0","mechanism_event_label":"A separate enzyme supports slower glutathione turnover.","subject":{"id":"2fa4de32-67d7-5e5c-8868-546c108768e8","slug":"chac2","display_name":"Human glutathione-specific gamma-glutamylcyclotransferase CHAC2","entity_type_key":"protein"},"object":{"id":"b44c9e27-4bbb-52d3-a022-14cddded5073","slug":"glutathione","display_name":"GSH","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"f6246f65-53a3-50a5-bb83-80d63173f9f0","stable_key":"db0fc92e-b5ef-5667-a4c5-3ef257edbc9b:glutathione-chac2-gsh-event","event_type":"biochemical_relationship","label":"A separate enzyme supports slower glutathione turnover.","description":"Purified human CHAC2 degraded reduced GSH with lower catalytic efficiency than CHAC1.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"2fa4de32-67d7-5e5c-8868-546c108768e8","slug":"chac2","display_name":"Human glutathione-specific gamma-glutamylcyclotransferase CHAC2","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"b44c9e27-4bbb-52d3-a022-14cddded5073","slug":"glutathione","display_name":"GSH","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/glutathione-research/27913623.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"ddf397c2cb8fd60423c89cab28a0b54d124f0e34e0564a32d6bca36841530694\", \"start_char\": 0, \"end_char\": 1617, \"text_sha256\": \"ddf397c2cb8fd60423c89cab28a0b54d124f0e34e0564a32d6bca36841530694\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified mammalian enzymes and expression comparison","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"CHAC1/CHAC2 substrate and kinetics comparison","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Human kinetics and yeast structure are distinct; this does not establish a universal turnover rate in vivo.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Glutathione research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"glutathione","display_name":"GSH","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Human and mouse enzymes; yeast structural homolog","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"A separate enzyme supports slower glutathione turnover.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[glutathione-p27913623] ChaC2, an Enzyme for Slow Turnover of Cytosolic Glutathione. (2017). https://pubmed.ncbi.nlm.nih.gov/27913623/ DOI: 10.1074/jbc.m116.727479","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cytosolic glutathione turnover","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"0cd56c9a-61f7-5e3f-96b0-81c8042380ca","evidence_kind":"source_excerpt","locator":"Lines 593-604","start_line":593,"end_line":604,"excerpt":"### glutathione-chac2-gsh\nPurified human CHAC2 degraded reduced GSH with lower catalytic efficiency than CHAC1.\nCondition category: normal\nnutrient_topic: Glutathione research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A separate enzyme supports slower glutathione turnover.\norganism: Human and mouse enzymes; yeast structural homolog\ntissue_or_cell_type: Cytosolic glutathione turnover\nexperimental_model: Purified mammalian enzymes and expression comparison\nlimitations: Human kinetics and yeast structure are distinct; this does not establish a universal turnover rate in vivo.\nexposure: CHAC1/CHAC2 substrate and kinetics comparison\nevidence_span: {\"source_cache\": \"artifacts/glutathione-research/27913623.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"ddf397c2cb8fd60423c89cab28a0b54d124f0e34e0564a32d6bca36841530694\", \"start_char\": 0, \"end_char\": 1617, \"text_sha256\": \"ddf397c2cb8fd60423c89cab28a0b54d124f0e34e0564a32d6bca36841530694\"}\n[glutathione-p27913623] ChaC2, an Enzyme for Slow Turnover of Cytosolic Glutathione. 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