{"id":"64e8f850-d671-562a-ab77-dddc7d01551c","stable_key":"4fef8d72-f107-5eb5-b2fb-483ca85465e0:k2-ggpp-sidechain","predicate":"uses","statement":"UBIAD1 synthesized MK-4 using GGPP as the isoprenyl side-chain source.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"f6f1585e-9550-5302-83f7-e38432d5bc5a","mechanism_event_label":"MK-4 production needs a side-chain donor as well as the vitamin K ring.","subject":{"id":"190c8a9f-60f4-5341-898e-187a0c697624","slug":"ubiad1","display_name":"Human UBIAD1 prenyltransferase","entity_type_key":"protein"},"object":{"id":"7e6d85c1-25b7-549b-9883-8e9d5d11ae3d","slug":"geranylgeranyl-diphosphate","display_name":"Geranylgeranyl diphosphate / GGPP","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"f6f1585e-9550-5302-83f7-e38432d5bc5a","stable_key":"4fef8d72-f107-5eb5-b2fb-483ca85465e0:k2-ggpp-sidechain-event","event_type":"biochemical_relationship","label":"MK-4 production needs a side-chain donor as well as the vitamin K ring.","description":"UBIAD1 synthesized MK-4 using GGPP as the isoprenyl side-chain source.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"5155b9d1-e835-54b4-9f61-4cf35b3e5227","slug":"menaquinone-4","display_name":"Menaquinone-4 / MK-4 / menatetrenone","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"190c8a9f-60f4-5341-898e-187a0c697624","slug":"ubiad1","display_name":"Human UBIAD1 prenyltransferase","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"7e6d85c1-25b7-549b-9883-8e9d5d11ae3d","slug":"geranylgeranyl-diphosphate","display_name":"Geranylgeranyl diphosphate / GGPP","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/k2-research/25874989.fulltext.txt\", \"locator\": \"Exact primary full-text span; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"bbd73607ba2570aa383c81c189b29dd19f1cbd7bf7acdd8343ecf3ee7dc5faf8\", \"start_char\": 24159, \"end_char\": 24399, \"text_sha256\": \"b680e2031495b2fee24a56c799e8cb2f64bbac3c6a3cb0d33592051f2cf41b9f\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Microsomal enzyme assays and mutagenesis","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Prenyl donors, reductant, magnesium and lipophilic statins","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"In-vitro substrate and assay context. Residual microsomal magnesium prevents concluding that synthesis is magnesium-independent; no human supplementation effect was tested.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin K2 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"k2","display_name":"Vitamin K2 / menaquinone family","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Human UBIAD1 expressed in Sf9 insect cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"MK-4 production needs a side-chain donor as well as the vitamin K ring.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[k2-p25874989] Functional characterization of the vitamin K2 biosynthetic enzyme UBIAD1. (2015). https://pubmed.ncbi.nlm.nih.gov/25874989/ DOI: 10.1371/journal.pone.0125737","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Microsomal prenylation","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"74b854e1-22a5-5554-b682-6da745817ba5","evidence_kind":"source_excerpt","locator":"Lines 201-212","start_line":201,"end_line":212,"excerpt":"### k2-ggpp-sidechain\nUBIAD1 synthesized MK-4 using GGPP as the isoprenyl side-chain source.\nCondition category: normal\nnutrient_topic: Vitamin K2 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: MK-4 production needs a side-chain donor as well as the vitamin K ring.\norganism: Human UBIAD1 expressed in Sf9 insect cells\ntissue_or_cell_type: Microsomal prenylation\nexperimental_model: Microsomal enzyme assays and mutagenesis\nlimitations: In-vitro substrate and assay context. Residual microsomal magnesium prevents concluding that synthesis is magnesium-independent; no human supplementation effect was tested.\nexposure: Prenyl donors, reductant, magnesium and lipophilic statins\nevidence_span: {\"source_cache\": \"artifacts/k2-research/25874989.fulltext.txt\", \"locator\": \"Exact primary full-text span; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"bbd73607ba2570aa383c81c189b29dd19f1cbd7bf7acdd8343ecf3ee7dc5faf8\", \"start_char\": 24159, \"end_char\": 24399, \"text_sha256\": \"b680e2031495b2fee24a56c799e8cb2f64bbac3c6a3cb0d33592051f2cf41b9f\"}\n[k2-p25874989] Functional characterization of the vitamin K2 biosynthetic enzyme UBIAD1. (2015). https://pubmed.ncbi.nlm.nih.gov/25874989/ DOI: 10.1371/journal.pone.0125737","model_system":"Microsomal enzyme assays and mutagenesis","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [k2-p25874989] Functional characterization of the vitamin K2 biosynthetic enzyme UBIAD1. (2015). https://pubmed.ncbi.nlm.nih.gov/25874989/ DOI: 10.1371/journal.pone.0125737","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"dfeae572-af3d-5042-a10e-e67596f9ab28","stable_key":"import-4fef8d72-f107-5eb5-b2fb-483ca85465e0","title":"Vitamin K2: menaquinone forms, carboxylation, recycling 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":"dc31aff21110d09b025c177e03b4c5ca8349d52bf5f962285fdbfcf660c0e4f6","revision_id":"850887db-34f6-55aa-9d3e-b8fd3a4a5de3","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}