Metabolism of Vitamin D3 by Human CYP27A1

Sawada, Natsumi; Sakaki, Toshiyuki; Ohta, Miho; Inouye, Kuniyo

doi:10.1006/bbrc.2000.3050

Cited by 101 publications

(79 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For example, CYP27A1 catalyzes the successive hydroxylation of vitamin D 3 (64) and cholesterol (65). Based on the time-dependent appearance of multiple reaction products during in vitro reactions, Sawada et al (64) concluded that CYP27A1 initially catalyzes hydroxylation at C-25 of vitamin D 3 , followed by a second hydroxylation at C-24, C-1, or C-26, yielding a complex mixture of a single monohydroxylated product and three or more dihydroxylated ones. No C-1 or C-24 monohydroxylation products were ob- 6.…”

Section: -Epiaristolochene 13-dihydroxylasementioning

confidence: 99%

Kinetic and Molecular Analysis of 5-Epiaristolochene 1,3-Dihydroxylase, a Cytochrome P450 Enzyme Catalyzing Successive Hydroxylations of Sesquiterpenes

Takahashi

Zhao

O’Maille

et al. 2005

Journal of Biological Chemistry

View full text Add to dashboard Cite

The final step of capsidiol biosynthesis is catalyzed by 5-epiaristolochene dihydroxylase (EAH), a cytochrome P450 enzyme that catalyzes the regio-and stereospecific insertion of two hydroxyl moieties into the bicyclic sesquiterpene 5-epiaristolochene (EA). Detailed kinetic studies using EA and the two possible monohydroxylated intermediates demonstrated the release of 1␤-hydroxy-EA ((OH)EA) at high EA concentrations and a 10-fold catalytic preference for 1␤(OH)EA versus 3␣(OH)EA, indicative of a preferred reaction order of hydroxylation at C-1, followed by that at C-3. Sequence alignments and homology modeling identified activesite residues tested for their contribution to substrate specificity and overall enzymatic activity. Mutants EAH-S368C and EAH-S368V exhibited wild-type catalytic efficiencies for 1␤(OH)EA biosynthesis, but were devoid of the successive hydroxylation activity for capsidiol biosynthesis. In contrast to EAH-S368C, EAH-S368V catalyzed the relative equal biosynthesis of 1␤(OH)EA, 2␤(OH)EA, and 3␤(OH)EA from EA with wild-type efficiency. Moreover, EAH-S368V converted ϳ1.5% of these monohydroxylated products to their respective ketone forms. Alanine and threonine mutations at position 368 were significantly compromised in their conversion rates of EA to capsidiol and correlated with 3.6-and 5.7-fold increases in their K m values for the 1␤(OH)EA intermediate, respectively. A role for Ile 486 in the successive hydroxylations of EA was also suggested by the EAH-I468A mutant, which produced significant amounts 1␤(OH)EA, but negligible amounts of capsidiol from EA. The altered product profile of the EAH-I486A mutant correlated with a 3.6-fold higher K m for EA and a 4.4-fold slower turnover rate (k cat ) for 1␤(OH)EA. These kinetic and mutational studies were correlated with substrate docking predictions to suggest how Ser 368 and Ile 486 might contribute to active-site topology, substrate binding, and substrate presentation to the oxo-Fe-heme reaction center.The mevalonate and methylerythritol phosphate pathways are responsible for the biosynthesis of isoprenoids, a diverse group of organic natural products found in animals, plants, fungi, insects, and bacteria. Isoprenoids are further divided into classes of primary and secondary metabolites. Isoprenoids that are primary metabolites include sterols, carotenoids, hormones, and long chain hydrocarbons used to tether particular enzymes to membrane systems, compounds essential for viability. Isoprenoids classified as secondary metabolites include monoterpenes, sesquiterpenes, diterpenes, and triterpenes, and many of these mediate interactions between organisms and their environments (1-5).Capsidiol is a bicyclic dihydroxylated sesquiterpene produced by several solanaceous plants in response to pathogen or elicitor challenge (6 -10) and is considered an important plant defense response because it can prevent the germination and growth of several fungal species (11). Capsidiol biosynthesis is regulated by the expression of two key enzymes (see Scheme 1...

show abstract

Section: -Epiaristolochene 13-dihydroxylasementioning

confidence: 99%

Kinetic and Molecular Analysis of 5-Epiaristolochene 1,3-Dihydroxylase, a Cytochrome P450 Enzyme Catalyzing Successive Hydroxylations of Sesquiterpenes

Takahashi

Zhao

O’Maille

et al. 2005

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…CYP27A1, also known as the sterol 27-hydroxylase, is a key enzyme in bile acid formation (6, 7). Recombinant CYP27A1 is able to catalyze multiple oxidation reactions with broad substrate specificity in vitro (8)(9)(10)(11)(12)(13)(14). However, it is a lowaffinity, high-capacity vitamin D 25-hydroxylase and is certainly involved in steroidogenesis.…”

mentioning

confidence: 99%

CYP2R1 is a major, but not exclusive, contributor to 25-hydroxyvitamin D production in vivo

Zhu

Ochalek

Kaufmann

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

262

140

View full text Add to dashboard Cite

Bioactivation of vitamin D consists of two sequential hydroxylation steps to produce 1α, 25-dihydroxyvitamin D 3 . It is clear that the second or 1α-hydroxylation step is carried out by a single enzyme, 25-hydroxyvitamin D 1α-hydroxylase CYP27B1. However, it is not certain what enzyme or enzymes are responsible for the initial 25-hydroxylation. An excellent case has been made for vitamin D 25-hydroxylase CYP2R1, but this hypothesis has not yet been tested. We have now produced Cyp2r1 −/− mice. These mice had greater than 50% reduction in serum 25-hydroxyvitamin D 3 . Curiously, the 1α,25-dihydroxyvitamin D 3 level in the serum remained unchanged. These mice presented no health issues. A double knockout of Cyp2r1 and Cyp27a1 maintained a similar circulating level of 25-hydroxyvitamin D 3 and 1α,25-dihydroxyvitamin D 3 . Our results support the idea that the CYP2R1 is the major enzyme responsible for 25-hydroxylation of vitamin D, but clearly a second, as-yet unknown, enzyme is another contributor to this important step in vitamin D activation. 25-Hydroxyvitamin D 1a-hydroxylase CYP27B1 (CYP27B1) has long been identified as the sole 25(OH)D 3 1α-hydroxylase in a number of species, including human (5), whereas the specific vitamin D 3 25-hydroxylase has yet to be elucidated. Many candidates have been proposed, but in vivo proof has yet to appear. Most of the potential 25-hydroxylases are primarily expressed in the liver, and all are members of the cytochrome P450 family (CYP2C11, CYP2D25, CYP27A1, CYP3A4, CYP2R1, and CYP2J2/3) (4). Among them, CYP27A1 and CYP2R1 are considered the most promising candidates for vitamin D 25-hydroxylation. CYP27A1, also known as the sterol 27-hydroxylase, is a key enzyme in bile acid formation (6, 7). Recombinant CYP27A1 is able to catalyze multiple oxidation reactions with broad substrate specificity in vitro (8)(9)(10)(11)(12)(13)(14). However, it is a lowaffinity, high-capacity vitamin D 25-hydroxylase and is certainly involved in steroidogenesis. Ablation of Cyp27a1 in mouse disrupted cholesterol metabolism and bile acid synthesis severely but did not alter vitamin D metabolism (15, 16). Indeed, these animals had supranormal serum 25(OH)D 3 levels (15). Patients with cerebrotendinous xanthomatosis caused by mutations in the Cyp27a1 gene show dysfunctions that result from reduced bile acid production, but generally do not present vitamin D-related pathology (17, 18). These findings suggest that CYP27A1 is a minor factor, if it plays a role at all, in 25(OH)D 3 synthesis in vivo. CYP2R1 was recently identified as vitamin D 25-hydroxylase in mouse and human through the screening of a liver cDNA library from Cyp27a1-null mice (19). Heterologous expression of CYP2R1 in HEK cells, yeast, and Escherichia coli revealed that CYP2R1 catalyzes 25-hydroxylation of both vitamin D 3 and vitamin D 2 at similar rate, and much more efficiently than CYP27A1 (19-21). The clinical relevance of CYP2R1 as vitamin D 25-hydroxylase is from a handful of patients of Nigerian and Saudi Arabian decent havi...

show abstract

“…CYP27A is also able to hydroxylate D 3 and D 3 metabolites at position C-25 (51) as well as at other positions on the secosteroid side chain (29,54). It has also been reported to be able to catalyze the 1␣-hydroxylation of 25-hydroxyvitamin D 3 (25OHD 3 ), albeit at a much lower rate than the transformation of D 3 into 25OHD 3 (3).…”

mentioning

confidence: 99%

High sensitivity of rat hepatic vitamin D₃-25 hydroxylaseCYP27Ato 1,25-dihydroxyvitamin D₃administration

Theodoropoulos

Demers

Petit

et al. 2003

American Journal of Physiology-Endocrinology and Metabolism

View full text Add to dashboard Cite

High sensitivity of the rat hepatic vitamin D3-25 hydroxylase CYP27A to 1,25-dihydroxyvitamin D 3 administration. Am J Physiol Endocrinol Metab 284: E138-E147, 2003. First published October 1, 2002 10.1152 10. /ajpendo.00303.2002 is considered the main vitamin D3 (D3)-25 hydroxylase in humans. Our purpose was to evaluate the effect of the D3 nutritional and hormonal status on hepatic CYP27A mRNA, cellular distribution, transcription rate, and enzyme activity. Studies were carried out in normal and in D-depleted rats supplemented with D3, 25OHD3, or 1,25(OH)2D3. CYP27A exhibited a significant gender difference and was observed throughout the hepatic acinus not only in hepatocytes but also in sinusoidal endothelial, stellate, and Kupffer cells. Neither D3 nor 25OHD3 influenced CYP27A mRNA levels. However, 1,25(OH)2D3 repletion led to a 60% decrease in CYP27A mRNA, which was accompanied by a 46% decrease in mitochondrial D3-25 hydroxylase activity. The effect of 1,25(OH)2D3 was mediated by a significant decrease in CYP27A transcription, whereas its mRNA half-life remained unchanged. Our data indicate that CYP27A is present in hepatic parenchymal and sinusoidal cells and that the gene transcript is not influenced by the D3 nutritional status but is transcriptionally regulated by 1,25(OH)2D3 exposure.bile acid biosynthesis; Kupffer cells; stellate cells; hepatocytes; sinusoidal endothelial cells THE SECOSTEROID VITAMIN D 3 (D 3 ) of endogenous or exogenous origin has, in its native form, no biological activity. Once in circulation, D 3 is efficiently taken up by the liver (26) and hydroxylated at C-25 by a mitochondrial mixed-function oxidase CYP27A [C 27 sterol hydroxylase (EC 1.14.13.15)] (15). In humans, the enzyme is presumed to be the only D 3 -25 hydroxylase (51). However, a microsomal D 3 -25 hydroxylase has also been reported in rodents (11), chickens (12), and pigs (35), but only the porcine enzyme (which has been termed CYP2D25) has been cloned to date (34,44).CYP27A is a cytochrome P-450 that catalyzes the first step in the oxidation of the cholesterol side chain in the secondary "acidic" bile acid biosynthesis pathway (13). CYP27A is also able to hydroxylate D 3 and D 3 metabolites at position C-25 (51) as well as at other positions on the secosteroid side chain (29, 54). It has also been reported to be able to catalyze the 1␣-hydroxylation of 25-hydroxyvitamin D 3 (25OHD 3 ), albeit at a much lower rate than the transformation of D 3 into 25OHD 3 (3). However, unlike the tight regulation by the D 3 endocrine system associated with the renal 25-hydroxyvitamin D 3 -1␣-hydroxylase, the sensitivity of the gene encoding CYP27A to D 3 or to D 3 metabolites has not been characterized. The presence of regulatory mechanisms related to the D 3 status as a modulator of the 25-hydroxylation of the vitamin is, however, a widely accepted notion, which rests on the studies of DeLuca's group in the early 1970s (Bhattacharyya and DeLuca, Refs. 10, 12). Several laboratories have attempted to evaluate the mechanism(s) inv...

show abstract

Metabolism of Vitamin D3 by Human CYP27A1

Cited by 101 publications

References 27 publications

Kinetic and Molecular Analysis of 5-Epiaristolochene 1,3-Dihydroxylase, a Cytochrome P450 Enzyme Catalyzing Successive Hydroxylations of Sesquiterpenes

Kinetic and Molecular Analysis of 5-Epiaristolochene 1,3-Dihydroxylase, a Cytochrome P450 Enzyme Catalyzing Successive Hydroxylations of Sesquiterpenes

CYP2R1 is a major, but not exclusive, contributor to 25-hydroxyvitamin D production in vivo

High sensitivity of rat hepatic vitamin D₃-25 hydroxylaseCYP27Ato 1,25-dihydroxyvitamin D₃administration

Contact Info

Product

Resources

About

Metabolism of Vitamin D3 by Human CYP27A1

Cited by 101 publications

References 27 publications

Kinetic and Molecular Analysis of 5-Epiaristolochene 1,3-Dihydroxylase, a Cytochrome P450 Enzyme Catalyzing Successive Hydroxylations of Sesquiterpenes

Kinetic and Molecular Analysis of 5-Epiaristolochene 1,3-Dihydroxylase, a Cytochrome P450 Enzyme Catalyzing Successive Hydroxylations of Sesquiterpenes

CYP2R1 is a major, but not exclusive, contributor to 25-hydroxyvitamin D production in vivo

High sensitivity of rat hepatic vitamin D3-25 hydroxylaseCYP27Ato 1,25-dihydroxyvitamin D3administration

Contact Info

Product

Resources

About

High sensitivity of rat hepatic vitamin D₃-25 hydroxylaseCYP27Ato 1,25-dihydroxyvitamin D₃administration