CYP27B1 (Vector pUC, Accession No. BC001776)

Length: 654 Sequence: atgacccaga ccctcaagta cgcctccaga gtgttccatc gcgtccgctg ggcgcccgag ttgggcgcct ccctaggcta ccgagagtac cactcagcac gccggagctt ggcagacatc ccaggcccct ctacgcccag ctttctggcc gaacttttct gcaagggggg gctgtcgagg ctacacgagc tgcaggtgca gggcgccgcg cacttcgggc cggtgtggct agccagcttt gggacagtgc gcaccgtgta cgtggctgcc cctgcactcg tcgaggagct gctgcgacag gagggacccc ggcccgagcg ctgcagcttc tcgccctgga cggagcaccg ccgctgccgc cagcgggctt gcggactgct cactgcggaa ggcgaagaat ggcaaaggct ccgcagtctc ctggccccgc tcctcctccg gcctcaagcg gccgcccgct acgccggaac cctgaacaac gtagtctgcg accttgtgcg gcgtctgagg cgccagcggg gacgtggcac ggggccgccc gccctggttc gggacgtggc gggggaattt tacaagttcg gactggaagg tgagtcccag gacagagctg ggcaggcgtc gggggcgccc taccagagcc tcccggaacc Protein function: A cytochrome P450 monooxygenase involved in vitamin D metabolism and in calcium and phosphorus homeostasis. Catalyzes the rate-limiting step in the activation of vitamin D in the kidney, namely the hydroxylation of 25-hydroxyvitamin D3/calcidiol at the C1alpha- position to form the hormonally active form of vitamin D3, 1alpha,25- dihydroxyvitamin D3/calcitriol that acts via the vitamin D receptor (VDR) (PubMed:10518789, PubMed:9486994, PubMed:22862690, PubMed:10566658, PubMed:12050193). Has 1alpha-hydroxylase activity on vitamin D intermediates of the CYP24A1-mediated inactivation pathway (PubMed:10518789, PubMed:22862690). Converts 24R,25-dihydroxyvitamin D3/secalciferol to 1-alpha,24,25-trihydroxyvitamin D3, an active ligand of VDR. Also active on 25-hydroxyvitamin D2 (PubMed:10518789). Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via FDXR/adrenodoxin reductase and FDX1/adrenodoxin (PubMed:22862690). [The UniProt Consortium]