{"id":"c1cafecd-5298-5778-9c0f-3b433d16987d","stable_key":"dc8975b1-95ff-5d9b-be17-a1c04610cca7:mo-xdh-hypoxanthine","predicate":"oxidizes","statement":"The primary article describes sequential XOR hydroxylation of hypoxanthine to xanthine and xanthine to urate.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"9732b7d2-48d1-57c8-91e8-e5438412dce9","mechanism_event_label":"Hypoxanthine enters the same two-step purine pathway.","subject":{"id":"8de34d8a-46dc-512c-a82f-d169747b496e","slug":"xdh","display_name":"Human xanthine oxidoreductase / XDH","entity_type_key":"protein"},"object":{"id":"99343398-bc89-52c4-b2f7-a0f6e3869a57","slug":"hypoxanthine","display_name":"Hypoxanthine","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"9732b7d2-48d1-57c8-91e8-e5438412dce9","stable_key":"dc8975b1-95ff-5d9b-be17-a1c04610cca7:mo-xdh-hypoxanthine-event","event_type":"biochemical_relationship","label":"Hypoxanthine enters the same two-step purine pathway.","description":"The primary article describes sequential XOR hydroxylation of hypoxanthine to xanthine and xanthine to urate.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"0a8b817b-52c5-5b98-b1d8-d6677651744c","slug":"xanthine","display_name":"Xanthine","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"8de34d8a-46dc-512c-a82f-d169747b496e","slug":"xdh","display_name":"Human xanthine oxidoreductase / XDH","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"99343398-bc89-52c4-b2f7-a0f6e3869a57","slug":"hypoxanthine","display_name":"Hypoxanthine","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/molybdenum-research/37713777.fulltext.txt\", \"locator\": \"Exact primary full-text span; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"a8092b2aa7328b59f0275dd8a37d2a2dbb5abb2a32236d0cab5fffcc1ddc671d\", \"start_char\": 1061, \"end_char\": 1244, \"text_sha256\": \"45575621674b6b2e232b2e7b9605ad8e6acde4977d3f22e20abebfcbfa0b4dcb\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human XDH variants with urate, superoxide and NO assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Xanthine, oxygen and inorganic nitrite assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Established reaction summarized in the primary article background; this paper directly assayed xanthine-based activity rather than newly establishing the hypoxanthine step.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Molybdenum research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"molybdenum","display_name":"Molybdenum","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Homo sapiens protein","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Hypoxanthine enters the same two-step purine pathway.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[mo-p37713777] Natural mutations of human XDH promote the nitrite (NO2-)-reductase capacity of xanthine oxidoreductase: A novel mechanism to promote redox health? (2023). https://pubmed.ncbi.nlm.nih.gov/37713777/ DOI: 10.1016/j.redox.2023.102864","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified human enzyme","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"0fb8824b-e9a8-5af5-8935-532f15209cbc","evidence_kind":"source_excerpt","locator":"Lines 755-766","start_line":755,"end_line":766,"excerpt":"### mo-xdh-hypoxanthine\nThe primary article describes sequential XOR hydroxylation of hypoxanthine to xanthine and xanthine to urate.\nCondition category: normal\nnutrient_topic: Molybdenum research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Hypoxanthine enters the same two-step purine pathway.\norganism: Homo sapiens protein\ntissue_or_cell_type: Purified human enzyme\nexperimental_model: Recombinant human XDH variants with urate, superoxide and NO assays\nlimitations: Established reaction summarized in the primary article background; this paper directly assayed xanthine-based activity rather than newly establishing the hypoxanthine step.\nexposure: Xanthine, oxygen and inorganic nitrite assays\nevidence_span: {\"source_cache\": \"artifacts/molybdenum-research/37713777.fulltext.txt\", \"locator\": \"Exact primary full-text span; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"a8092b2aa7328b59f0275dd8a37d2a2dbb5abb2a32236d0cab5fffcc1ddc671d\", \"start_char\": 1061, \"end_char\": 1244, \"text_sha256\": \"45575621674b6b2e232b2e7b9605ad8e6acde4977d3f22e20abebfcbfa0b4dcb\"}\n[mo-p37713777] Natural mutations of human XDH promote the nitrite (NO2-)-reductase capacity of xanthine oxidoreductase: A novel mechanism to promote redox health? (2023). https://pubmed.ncbi.nlm.nih.gov/37713777/ DOI: 10.1016/j.redox.2023.102864","model_system":"Recombinant human XDH variants with urate, superoxide and NO assays","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [mo-p37713777] Natural mutations of human XDH promote the nitrite (NO2-)-reductase capacity of xanthine oxidoreductase: A novel mechanism to promote redox health? (2023). https://pubmed.ncbi.nlm.nih.gov/37713777/ DOI: 10.1016/j.redox.2023.102864","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"1aa6da60-8284-5252-8dd9-ac2250d5ced5","stable_key":"import-dc8975b1-95ff-5d9b-be17-a1c04610cca7","title":"Molybdenum: cofactor assembly, sulfur metabolism 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":"143147eb9ac7fe750bdd33bb50d7773bc0cd49cc94faf219aebce3c3d760dd8f","revision_id":"90c2239d-290b-5e16-815a-f94d30569ebd","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}