1,25-dihydroxyvitamin D(3) 24-hydroxylase, mitochondrial (24-OHase) (Vitamin D(3) 24-hydroxylase) (EC 1.14.15.16) (Cytochrome P450 24A1) (Cytochrome P450-CC24)
1_MSSPI 6_ SKSRS 11_ LAAFL 16_ QQLRS 21_ PRQPP 26_ RLVTS 31_ TAYTS 36_ PQPRE 41_ VPVCP 46_ LTAGG 51_ ETQNA 56_ AALPG 61_ PTSWP 66_ LLGSL 71_ LQILW 76_ KGGLK 81_ KQHDT 86_ LVEYH 91_ KKYGK 96_ IFRMK 101_ LGSFE 106_ SVHLG 111_ SPCLL 116_ EALYR 121_ TESAY 126_ PQRLE 131_ IKPWK 136_ AYRDY 141_ RKEGY 146_ GLLIL 151_ EGEDW 156_ QRVRS 161_ AFQKK 166_ LMKPG 171_ EVMKL 176_ DNKIN 181_ EVLAD 186_ FMGRI 191_ DELCD 196_ ERGHV 201_ EDLYS 206_ ELNKW 211_ SFESI 216_ CLVLY 221_ EKRFG 226_ LLQKN 231_ AGDEA 236_ VNFIM 241_ AIKTM 246_ MSTFG 251_ RMMVT 256_ PVELH 261_ KSLNT 266_ KVWQD 271_ HTLAW 276_ DTIFK 281_ SVKAC 286_ IDNRL 291_ EKYSQ 296_ QPSAD 301_ FLCDI 306_ YHQNR 311_ LSKKE 316_ LYAAV 321_ TELQL 326_ AAVET 331_ TANSL 336_ MWILY 341_ NLSRN 346_ PQVQQ 351_ KLLKE 356_ IQSVL 361_ PENQV 366_ PRAED 371_ LRNMP 376_ YLKAC 381_ LKESM 386_ RLTPS 391_ VPFTT 396_ RTLDK 401_ ATVLG 406_ EYALP 411_ KGTVL 416_ MLNTQ 421_ VLGSS 426_ EDNFE 431_ DSSQF 436_ RPERW 441_ LQEKE 446_ KINPF 451_ AHLPF 456_ GVGKR 461_ MCIGR 466_ RLAEL 471_ QLHLA 476_ LCWIV 481_ RKYDI 486_ QATDN 491_ EPVEM 496_ LHSGT 501_ LVPSR 506_ELPIA
1: A cytochrome P450 monooxygenase with a key role in vitamin D catabolism and calcium homeostasis. Via C24- and C23-oxidation pathways, catalyzes the inactivation of both the vitamin D precursor calcidiol (25-hydroxyvitamin D(3)) and the active hormone calcitriol (1-alpha,25-dihydroxyvitamin D(3)) (PubMed:11012668, PubMed:15574355, PubMed:16617161, PubMed:24893882, PubMed:29461981, PubMed:8679605). With initial hydroxylation at C-24 (via C24-oxidation pathway), performs a sequential 6-step oxidation of calcitriol leading to the formation of the biliary metabolite calcitroic acid (PubMed:15574355, PubMed:24893882). With initial hydroxylation at C-23 (via C23-oxidation pathway), catalyzes sequential oxidation of calcidiol leading to the formation of 25(OH)D3-26,23-lactone as end product (PubMed:11012668, PubMed:8679605). Preferentially hydroxylates at C-25 other vitamin D active metabolites, such as CYP11A1-derived secosteroids 20S-hydroxycholecalciferol and 20S,23-dihydroxycholecalciferol (PubMed:25727742). 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:8679605)