Target type: molecularfunction
Catalysis of the reaction: calcidiol + 2 H+ + O2 + 2 reduced [adrenodoxin] = (23S)-23,25-dihydroxycalciol + H2O + 2 oxidized [adrenodoxin]. [PMID:22100522, PMID:30205156, RHEA:46616]
25-Hydroxycholecalciferol-23-hydroxylase activity is an enzymatic function that catalyzes the hydroxylation of 25-hydroxycholecalciferol (25-OH-D3) at the 23-carbon position, yielding 23,25-dihydroxycholecalciferol (23,25-(OH)2D3). This step is crucial in the biosynthesis of the active form of vitamin D, calcitriol (1,25-dihydroxycholecalciferol, 1,25-(OH)2D3). The enzyme responsible for this activity is CYP27B1, also known as 1α-hydroxylase. While not directly involved in the activation of vitamin D, this enzyme plays a vital role in regulating the synthesis of calcitriol by acting as a shunt pathway, diverting 25-OH-D3 away from the main pathway leading to calcitriol production. The activity of CYP27B1 is regulated by a complex interplay of factors, including vitamin D levels, parathyroid hormone, and calcium. This regulation ensures appropriate levels of 23,25-(OH)2D3, which is believed to have distinct biological roles compared to calcitriol, potentially influencing calcium homeostasis and bone metabolism.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| 1,25-dihydroxyvitamin D(3) 24-hydroxylase, mitochondrial | A 1,25-dihydroxyvitamin D(3) 24-hydroxylase, mitochondrial that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q07973] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| ketoconazole | 1-acetyl-4-(4-{[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy}phenyl)piperazine : A dioxolane that is 1,3-dioxolane which is substituted at positions 2, 2, and 4 by imidazol-1-ylmethyl, 2,4-dichlorophenyl, and [para-(4-acetylpiperazin-1-yl)phenoxy]methyl groups, respectively. | dichlorobenzene; dioxolane; ether; imidazoles; N-acylpiperazine; N-arylpiperazine | |
| liarozole | liarozole: inhibits all-trans-retinoic acid 4-hydroxylase; effective against hormone-dependent and hormone-independent tumors; R 75251 is chlorohydrate of R 61405; a potent inhibitor of retinoic acid metabolism; USAN name - liarozole fumarate | benzimidazoles | |
| ketoconazole | (2R,4S)-ketoconazole : A cis-1-acetyl-4-(4-{[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy}phenyl)piperazine which dioxolane moiety has (2R,4S)-configuration. | cis-1-acetyl-4-(4-{[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy}phenyl)piperazine | |
| calcitriol | dihydroxy-vitamin D3: as a major in vitro metabolite of 1alpha,25-dihydroxyvitamin D3, produced in primary cultures of neonatal human keratinocytes | D3 vitamins; hydroxycalciol; triol | antineoplastic agent; antipsoriatic; bone density conservation agent; calcium channel agonist; calcium channel modulator; hormone; human metabolite; immunomodulator; metabolite; mouse metabolite; nutraceutical |