{"id":"adf41383-89c5-5087-9f4e-fa119d7e5b2f","stable_key":"1deb434a-3547-51a0-a038-87b1ce79ec38:vd-act-cyp27b1-d2","predicate":"produces","statement":"Human CYP27B1 1alpha-hydroxylated 25-hydroxyvitamin D2 in phospholipid vesicles; low-substrate catalytic efficiency was similar to that measured for calcifediol.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"5835de59-6dd4-54cb-864c-1010ccaef497","mechanism_event_label":"CYP27B1 completes activation of the D2 precursor.","subject":{"id":"a1d0238c-7529-5175-b5f9-71dc9bc61ed5","slug":"cyp27b1","display_name":"Vitamin D 1-alpha-hydroxylase / CYP27B1","entity_type_key":"protein"},"object":{"id":"77a8ef8f-1309-58e1-a915-8ba79e0d0038","slug":"1-25-dihydroxyvitamin-d2","display_name":"1-alpha,25-Dihydroxyvitamin D2","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"5835de59-6dd4-54cb-864c-1010ccaef497","stable_key":"1deb434a-3547-51a0-a038-87b1ce79ec38:vd-act-cyp27b1-d2-event","event_type":"biochemical_relationship","label":"CYP27B1 completes activation of the D2 precursor.","description":"Human CYP27B1 1alpha-hydroxylated 25-hydroxyvitamin D2 in phospholipid vesicles; low-substrate catalytic efficiency was similar to that measured for calcifediol.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"a1d0238c-7529-5175-b5f9-71dc9bc61ed5","slug":"cyp27b1","display_name":"Vitamin D 1-alpha-hydroxylase / CYP27B1","entity_type_key":"protein"},"role":"enzyme","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"92118f85-ffc4-5f77-bfca-4b033b001548","slug":"25-hydroxyvitamin-d2","display_name":"25-Hydroxyvitamin D2","entity_type_key":"small_molecule"},"role":"substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"77a8ef8f-1309-58e1-a915-8ba79e0d0038","slug":"1-25-dihydroxyvitamin-d2","display_name":"1-alpha,25-Dihydroxyvitamin D2","entity_type_key":"small_molecule"},"role":"product","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"34590b7b-744d-5654-8b8c-8dc447c667bf","slug":"fdx1","display_name":"Human adrenodoxin / FDX1","entity_type_key":"protein"},"role":"electron_transfer_partner","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"57304e14-8bdf-5490-a897-058461023f2e","slug":"fdxr","display_name":"Human ferredoxin reductase / FDXR","entity_type_key":"protein"},"role":"reductase","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"4aba2a5e-8d06-5304-bb01-c0402b225a94","slug":"nadph","display_name":"NADPH","entity_type_key":"small_molecule"},"role":"electron_source","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"false","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_location","value_text":"Primary Tables 3-5, Figure 6A and Experimental procedures; full text retrieved.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Partially purified human CYP27B1 membrane assay","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"5-40 nM CYP27B1; 15 micromolar FDX1, 0.4 micromolar FDXR, 50 micromolar NADPH; 2 min at 37 C. 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Table 5/Figure 6A.\ncross_nutrient: false\nevidence_location: Primary Tables 3-5, Figure 6A and Experimental procedures; full text retrieved.\nnutrient: Vitamin D2 and D3\n[tang2012] Expression of human CYP27B1 in Escherichia coli and characterization in phospholipid vesicles. (2012). https://pubmed.ncbi.nlm.nih.gov/22862690/ DOI: 10.1111/j.1742-4658.2012.08736.x","model_system":"Partially purified human CYP27B1 membrane assay","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [tang2012] Expression of human CYP27B1 in Escherichia coli and characterization in phospholipid vesicles. 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