{"id":"06832a4d-6f8f-5639-8304-bb8b71edb29f","stable_key":"ec174d5a-4903-5745-8646-df0e9d4265e8:folate-methyl-bhmt-zinc","predicate":"required_for_activity_of","statement":"Chemical zinc removal inactivated human BHMT; zinc reconstitution restored its activity and metal content.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"05c48a3b-9190-5003-ae06-5e9b58fa908a","mechanism_event_label":"The betaine route requires a zinc-containing enzyme.","subject":{"id":"49c806c2-7041-5020-8b3b-fa04ffa122ac","slug":"zinc-ion","display_name":"Zinc(II) ion","entity_type_key":"ion"},"object":{"id":"a770de2f-556e-51b7-a18e-fb144bccf8d5","slug":"bhmt","display_name":"Betaine-homocysteine S-methyltransferase / BHMT","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"05c48a3b-9190-5003-ae06-5e9b58fa908a","stable_key":"ec174d5a-4903-5745-8646-df0e9d4265e8:folate-methyl-bhmt-zinc-event","event_type":"biochemical_relationship","label":"The betaine route requires a zinc-containing enzyme.","description":"Chemical zinc removal inactivated human BHMT; zinc reconstitution restored its activity and metal content.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"f2ed20a5-c46b-5d60-9368-35d4969b6980","slug":"betaine","display_name":"Betaine","entity_type_key":"small_molecule"},"role":"methyl donor","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"49c806c2-7041-5020-8b3b-fa04ffa122ac","slug":"zinc-ion","display_name":"Zinc(II) ion","entity_type_key":"ion"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"a770de2f-556e-51b7-a18e-fb144bccf8d5","slug":"bhmt","display_name":"Betaine-homocysteine S-methyltransferase / BHMT","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"Zinc supports parallel remethylation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human BHMT and human liver-derived BHMT.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Demetallation is not dietary zinc deficiency.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Folate and folic acid research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"folate","display_name":"Folate (vitamin B9)","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The betaine route requires a zinc-containing enzyme.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[millian-1998] Human betaine-homocysteine methyltransferase is a zinc metalloenzyme (1998). https://pubmed.ncbi.nlm.nih.gov/9681996/ DOI: 10.1006/abbi.1998.0757","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified protein","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"3e1514fd-c12d-5b80-aa7b-b588156c12b1","evidence_kind":"source_excerpt","locator":"Lines 622-632","start_line":622,"end_line":632,"excerpt":"### folate-methyl-bhmt-zinc\nChemical zinc removal inactivated human BHMT; zinc reconstitution restored its activity and metal content.\nCondition category: normal\nnutrient_topic: Folate and folic acid research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The betaine route requires a zinc-containing enzyme.\norganism: Homo sapiens\ntissue_or_cell_type: Purified protein\nexperimental_model: Recombinant human BHMT and human liver-derived BHMT.\nlimitations: Demetallation is not dietary zinc deficiency.\ncross_nutrient: Zinc supports parallel remethylation.\n[millian-1998] Human betaine-homocysteine methyltransferase is a zinc metalloenzyme (1998). https://pubmed.ncbi.nlm.nih.gov/9681996/ DOI: 10.1006/abbi.1998.0757","model_system":"Recombinant human BHMT and human liver-derived BHMT.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [millian-1998] Human betaine-homocysteine methyltransferase is a zinc metalloenzyme (1998). https://pubmed.ncbi.nlm.nih.gov/9681996/ DOI: 10.1006/abbi.1998.0757","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"f4ce1a62-9582-5f7a-84f5-a23d0e1bfc68","stable_key":"import-ec174d5a-4903-5745-8646-df0e9d4265e8","title":"Folate and folic acid: 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":"e564d43989ece1006c95cd0748e9af6fe369074599a2eebba0a99ebff864b0dd","revision_id":"76674a33-b2a1-5e41-b71b-44399038ff7c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}