Rhea - reaction knowledgebase

Enzymes

UniProtKB ^help_outline	5 proteins
Enzyme class ^help_outline	EC 1.14.15.15 cholestanetriol 26-monooxygenase
GO Molecular Function ^help_outline	GO:0047748 cholestanetetraol 26-dehydrogenase activity

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Name ^help_outline 5β-cholestane-3α,7α,12α-triol Identifier CHEBI:16496 (CAS: 547-96-6) ^help_outline Charge 0 Formula C27H48O3 InChIKey^help_outline RIVQQZVHIVNQFH-XJZYBRFWSA-N SMILES^help_outline [H][C@@]12C[C@H](O)CC[C@]1(C)[C@@]1([H])C[C@H](O)[C@]3(C)[C@]([H])(CC[C@@]3([H])[C@]1([H])[C@H](O)C2)[C@H](C)CCCC(C)C 2D coordinates Mol file for the small molecule Search links Involved in 4 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline H⁺ Identifier CHEBI:15378 Charge 1 Formula H InChIKey^help_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILES^help_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,176 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline O₂ Identifier CHEBI:15379 (CAS: 7782-44-7) ^help_outline Charge 0 Formula O2 InChIKey^help_outline MYMOFIZGZYHOMD-UHFFFAOYSA-N SMILES^help_outline O=O 2D coordinates Mol file for the small molecule Search links Involved in 2,648 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name^help_outline reduced [adrenodoxin] Identifier RHEA-COMP:9998 Reactive part ^help_outline
- Name ^help_outline [2Fe-2S]¹⁺ Identifier CHEBI:33738 Charge 1 Formula Fe2S2 InChIKey^help_outline MAGIRAZQQVQNKP-UHFFFAOYSA-N SMILES^help_outline S1[Fe]S[Fe+]1 2D coordinates Mol file for the small molecule Search links Involved in 236 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Search links Involved in 54 reaction(s) Find proteins in UniProtKB for this molecule
Name ^help_outline (25R)-3α,7α,12α-trihydroxy-5β-cholestan-26-oate Identifier CHEBI:58734 Charge -1 Formula C27H45O5 InChIKey^help_outline CNWPIIOQKZNXBB-WBYPBBSPSA-M SMILES^help_outline [H][C@@]12C[C@H](O)CC[C@]1(C)[C@@]1([H])C[C@H](O)[C@]3(C)[C@]([H])(CC[C@@]3([H])[C@]1([H])[C@H](O)C2)[C@H](C)CCC[C@@H](C)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline H₂O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) ^help_outline Charge 0 Formula H2O InChIKey^help_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILES^help_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,048 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name^help_outline oxidized [adrenodoxin] Identifier RHEA-COMP:9999 Reactive part ^help_outline
- Name ^help_outline [2Fe-2S]²⁺ Identifier CHEBI:33737 Charge 2 Formula Fe2S2 InChIKey^help_outline XSOVBBGAMBLACL-UHFFFAOYSA-N SMILES^help_outline S1[Fe+]S[Fe+]1 2D coordinates Mol file for the small molecule Search links Involved in 236 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Search links Involved in 54 reaction(s) Find proteins in UniProtKB for this molecule

Cross-references

	RHEA:34631	RHEA:34632	RHEA:34633	RHEA:34634
Reaction direction	undefined	left-to-right	right-to-left	bidirectional
UniProtKB ^help_outline	5 proteins	4 proteins
EC numbers ^help_outline	1.14.15.15
Gene Ontology ^help_outline	GO:0047748
KEGG ^help_outline				R11142
MetaCyc ^help_outline		RXN-13690

Publications

Purification, characterization, and directed evolution study of a vitamin D3 hydroxylase from Pseudonocardia autotrophica.

Fujii Y., Kabumoto H., Nishimura K., Fujii T., Yanai S., Takeda K., Tamura N., Arisawa A., Tamura T.

Vitamin D(3) (VD(3)) is a fat-soluble prohormone that plays a crucial role in bone metabolism, immunity, and control of cell proliferation and cell differentiation in mammals. The actinomycete Pseudonocardia autotrophica is capable of bioconversion of VD(3) into its physiologically active forms, n ... >> More

Vitamin D(3) (VD(3)) is a fat-soluble prohormone that plays a crucial role in bone metabolism, immunity, and control of cell proliferation and cell differentiation in mammals. The actinomycete Pseudonocardia autotrophica is capable of bioconversion of VD(3) into its physiologically active forms, namely, 25(OH)VD(3) or 1alpha,25(OH)(2)VD(3). In this study, we isolated and characterized Vdh (vitamin D(3) hydroxylase), which hydroxylates VD(3) from P. autotrophica NBRC 12743. The vdh gene encodes a protein containing 403 amino acids with a molecular weight of 44,368Da. This hydroxylase was found to be homologous with the P450 belonging to CYP107 family. Vdh had the same ratio of the V(max) values for VD(3) 25-hydroxylation and 25(OH)VD(3) 1alpha-hydroxylation, while other enzymes showed preferential regio-specific hydroxylation on VD(3). We characterized a collection of Vdh mutants obtained by random mutagenesis and obtained a Vdh-K1 mutant by the combination of four amino acid substitutions. Vdh-K1 showed one-order higher VD(3) 25-hydroxylase activity than the wild-type enzyme. Biotransformation of VD(3) into 25(OH)VD(3) was successfully accomplished with a Vdh-expressed recombinant strain of actinobacterium Rhodococcus erythropolis. Vdh may be a useful enzyme for the production of physiologically active forms of VD(3) by a single cytochrome P450. << Less

Biochem. Biophys. Res. Commun. 385:170-175(2009) [PubMed] [EuropePMC]

This publication is cited by 1 other entry.
Putative helix F contributes to regioselectivity of hydroxylation in mitochondrial cytochrome P450 27A1.

Pikuleva I.A., Puchkaev A., Bjoerkhem I.

On the basis of alignment with structurally characterized cytochromes P450 (P450s), we have identified the putative F and G helices of mitochondrial P450s 27A1 and 11A. We introduced substitutions at Phe-207, Ile-211, and Phe-215 within putative helix F and at Trp-235 and Tyr-238 within putative h ... >> More

On the basis of alignment with structurally characterized cytochromes P450 (P450s), we have identified the putative F and G helices of mitochondrial P450s 27A1 and 11A. We introduced substitutions at Phe-207, Ile-211, and Phe-215 within putative helix F and at Trp-235 and Tyr-238 within putative helix G in P450 27A1 and compared wild type and mutants with respect to catalytic activity, product pattern, substrate binding, formation of hydrogen peroxide, and interaction with redox partner. Results indicate that the mutated residues are important for delivery of the correctly oriented substrate to the P450 active site. The I211K and F215K mutations, for example, affected the regioselectivity of P450 27A1-dependent hydroxylation reactions and conferred the P450 capacity to cleave the C-C bond of the substrate during the catalytic cycle. Studies of P450 11A1 indicate that Phe-202 has functions similar to those of its counterpart in P450 27A1 (Phe-215). We propose that putative helices F and G form the sides of the substrate-access channel, thus providing the additional mechanism to control regioselectivity of hydroxylation in mitochondrial P450s. << Less

Biochemistry 40:7621-7629(2001) [PubMed] [EuropePMC]

This publication is cited by 3 other entries.
Characterization of human sterol 27-hydroxylase. A mitochondrial cytochrome P-450 that catalyzes multiple oxidation reaction in bile acid biosynthesis.

Cali J.J., Russell D.W.

The enzyme sterol 27-hydroxylase catalyzes the first step in the oxidation of the side chain of sterol intermediates in the bile acid synthesis pathway. Human sterol 27-hydroxylase cDNAs were isolated from a liver cDNA library by cross-hybridization with a previously cloned rabbit cDNA probe. DNA ... >> More

The enzyme sterol 27-hydroxylase catalyzes the first step in the oxidation of the side chain of sterol intermediates in the bile acid synthesis pathway. Human sterol 27-hydroxylase cDNAs were isolated from a liver cDNA library by cross-hybridization with a previously cloned rabbit cDNA probe. DNA sequence analysis of hybridization-positive clones predicted a human sterol 27-hydroxylase consisting of a 33-amino-acid mitochondrial signal sequence followed by a mature protein of 498 amino acids. RNA blotting experiments demonstrated sterol 27-hydroxylase mRNAs of approximately 1.8 to 2.2 kilobases in liver and fibroblast cells. The steady state levels of the mRNA did not change when cultured cells were grown in the presence or absence of sterols. Introduction of the sterol 27-hydroxylase cDNA into Simian COS cells resulted in the expression of active enzyme capable of catalyzing multiple oxidation reactions (R-CH3----R-CH2OH----R-COOH) at carbon 27 of sterol intermediates of the bile acid synthesis pathway. << Less

J. Biol. Chem. 266:7774-7778(1991) [PubMed] [EuropePMC]

This publication is cited by 3 other entries.
Sterol 27-hydroxylase in bile acid biosynthesis. Mechanism of oxidation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,27-tetrol into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid.

Holmberg-Betsholtz I., Lund E., Bjorkhem I., Wikvall K.

The sequence of reactions catalyzed by sterol 27-hydroxylase (CYP27) in the oxidation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,27-tetrol into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid was studied with apparently homogeneous preparations of the cytochrome P-450 from rabbit l ... >> More

The sequence of reactions catalyzed by sterol 27-hydroxylase (CYP27) in the oxidation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,27-tetrol into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid was studied with apparently homogeneous preparations of the cytochrome P-450 from rabbit liver mitochondria. Conditions are described for the formation and characterization of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestane-27-al as an enzymatically generated intermediate in the oxidation process. Incubation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol or 5 beta-cholestane-3 alpha,7 alpha,12 alpha,27-tetrol with sterol 27-hydroxylase in 18O2 atmosphere resulted in the incorporation of one or two 18O atoms in the carboxyl group of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid. Similar incubations with 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestane-27-al resulted in the incorporation of one 18O atom in the 27-carboxyl group. The results strongly indicate that the sterol 27-hydroxylase performs multiple monooxygenations in the conversion of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid. The following reaction sequence (Reaction 1) at carbon 27 is proposed. [formula: see text] Reaction 1. << Less

J Biol Chem 268:11079-11085(1993) [PubMed] [EuropePMC]

This publication is cited by 3 other entries.
Activities of recombinant human cytochrome P450c27 (CYP27) which produce intermediates of alternative bile acid biosynthetic pathways.

Pikuleva I.A., Babiker A., Waterman M.R., Bjoerkhem I.

The primary physiological significance of cytochrome P450c27 (CYP27) has been associated with its role in the degradation of the side chain of C27 steroids in the hepatic bile acid biosynthesis pathway, which begins with 7alpha-hydroxylation of cholesterol in liver. However, recognition that in hu ... >> More

The primary physiological significance of cytochrome P450c27 (CYP27) has been associated with its role in the degradation of the side chain of C27 steroids in the hepatic bile acid biosynthesis pathway, which begins with 7alpha-hydroxylation of cholesterol in liver. However, recognition that in humans P450c27 is a widely or ubiquitously expressed mitochondrial P450, and that there are alternative pathways of bile acid synthesis which begin with 27-hydroxylation of cholesterol catalyzed by P450c27, suggests the need to reevaluate the role of this enzyme and its catalytic properties. 27-Hydroxycholesterol was thought to be the only product formed upon reaction of P450c27 with cholesterol. However, the present study demonstrates that recombinant human P450c27 is also able to further oxidize 27-hydroxycholesterol giving first an aldehyde and then 3beta-hydroxy-5-cholestenoic acid. Kinetic data indicate that in a reconstituted system, after 27-hydroxycholesterol is formed from cholesterol, it is released from the P450 and then competes with cholesterol for reentry the enzyme active site for further oxidation. Under subsaturating substrate concentrations, the efficiencies of oxidation of 27-hydroxycholesterol and 3beta-hydroxy-5-cholestenal to the acid by human P450c27 are greater than the efficiency of hydroxylation of cholesterol to 27-hydroxycholesterol indicating that the first hydroxylation step in the overall conversion of cholesterol into 3beta-hydroxy-5-cholestenoic acid is rate-limiting. Interestingly, 3beta-hydroxy-5-cholestenoic acid was found to be further metabolized by the recombinant human P450c27, giving two monohydroxylated products with the hydroxyl group introduced at different positions on the steroid nucleus. << Less

J. Biol. Chem. 273:18153-18160(1998) [PubMed] [EuropePMC]

This publication is cited by 4 other entries.
Oxidation of 5 beta-cholestane-3 alpha,7 alpha, 12 alpha-triol into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid by cytochrome P-450(26) from rabbit liver mitochondria.

Dahlback H., Holmberg I.

The mitochondrial cytochrome P-450(26), previously shown to catalyze 26-hydroxylation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol, was found to convert this substrate also into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid. The formation of 3 alpha,7 alpha,12 alpha-trihydr ... >> More

The mitochondrial cytochrome P-450(26), previously shown to catalyze 26-hydroxylation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol, was found to convert this substrate also into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid. The formation of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid increased with increasing incubation time and enzyme concentration. Addition of NAD+ to the incubation mixture did not increase the formation of the acid. Incubation with 5 beta-cholestane-3 alpha,7 alpha,12 alpha,26-tetrol, cytochrome P-450(26), ferredoxin, ferredoxin reductase and NADPH resulted in one major product, 3 alpha,7 alpha, 12 alpha-trihydroxy-5 beta-cholestanoic acid. The cytochrome P-450 required both ferredoxin, ferredoxin reductase and NADPH for activity. NADPH could not be replaced by NAD+ or NADP+. << Less

Biochem Biophys Res Commun 167:391-395(1990) [PubMed] [EuropePMC]

This publication is cited by 1 other entry.
Cloning, structure, and expression of the mitochondrial cytochrome P-450 sterol 26-hydroxylase, a bile acid biosynthetic enzyme.

Andersson S., Davis D.L., Dahlbaeck H., Joernvall H., Russell D.W.

The conversion of cholesterol into bile acids in the liver represents the major catabolic pathway for the removal of cholesterol from the body. In this complex biosynthetic pathway, at least 10 enzymes modify both the ring structure and side chain of cholesterol, resulting in the formation of the ... >> More

The conversion of cholesterol into bile acids in the liver represents the major catabolic pathway for the removal of cholesterol from the body. In this complex biosynthetic pathway, at least 10 enzymes modify both the ring structure and side chain of cholesterol, resulting in the formation of the primary bile acids, cholic acid, and chenodeoxycholic acid. To gain insight into the details and regulation of this pathway, we have used protein sequencing and molecular cloning techniques to isolate and characterize a cDNA encoding the rabbit mitochondrial sterol 26-hydroxylase. This enzyme catalyzes the first step in the oxidation of the side chain of sterol intermediates in the biosynthesis of bile acids. The structure of the sterol 26-hydroxylase, as deduced by both DNA sequence analysis of the cDNA and protein sequence analysis, reveals it to be a mitochondrial cytochrome P-450. A signal sequence of 36 residues precedes a coding region of 499 amino acids, predicting a molecular weight of 56,657 for the mature protein. The identity of the 26-hydroxylase cDNA was further confirmed by expression in monkey COS cells employing a versatile eukaryotic expression vector. Blotting experiments revealed that the mRNA for this enzyme is expressed in many tissues and that it is encoded by a low copy number gene in the rabbit genome. << Less

J. Biol. Chem. 264:8222-8229(1989) [PubMed] [EuropePMC]

This publication is cited by 1 other entry.
Hydroxylations in biosynthesis of bile acids. Isolation of a cytochrome P-450 from rabbit liver mitochondria catalyzing 26-hydroxylation of C27-steroids.

Wikvall K.

A cytochrome P-450 catalyzing 26-hydroxylation of C27-steroids was purified from liver mitochondria of untreated rabbits. The enzyme fraction contained 10 nmol of cytochrome P-450/mg of protein and showed only one protein band with a minimum Mr = 53,000 upon sodium dodecyl sulfate-polyacrylamide g ... >> More

A cytochrome P-450 catalyzing 26-hydroxylation of C27-steroids was purified from liver mitochondria of untreated rabbits. The enzyme fraction contained 10 nmol of cytochrome P-450/mg of protein and showed only one protein band with a minimum Mr = 53,000 upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified mitochondrial cytochrome P-450 showed apparent molecular weight similar to microsomal cytochromes P-450LM4 but differed in spectral and catalytic properties from these microsomal isozymes. The purified cytochrome P-450 catalyzed 26-hydroxylation of cholesterol, 5-cholestene-3 beta,7 alpha-diol, 7 alpha-hydroxy-4-cholesten-3-one, 5 beta-cholestane-3 alpha,7 alpha-diol, and 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol up to 1000 times more efficiently than the mitochondria. The cytochrome P-450 required both ferredoxin and ferredoxin reductase for catalytic activity. Microsomal NADPH-cytochrome P-450 reductase could not replace ferredoxin and ferredoxin reductase. The cytochrome P-450 was inactive in 7 alpha-, 12 alpha- and 25-hydroxylations of C27-steroids. The results suggest that mitochondrial 26-hydroxylation of various C27-steroids is catalyzed by the same species of cytochrome P-450. << Less

J Biol Chem 259:3800-3804(1984) [PubMed] [EuropePMC]

This publication is cited by 1 other entry.

Comments

Multi-step reaction: RHEA:14373 and RHEA:40231 and RHEA:34627.

RHEA:34631 5beta-cholestane-3alpha,7alpha,12alpha-triol + 5 H(+) + 3 O2 + 6 reduced [adrenodoxin] = (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate + 4 H2O + 6 oxidized [adrenodoxin]

Enzymes

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Cross-references

Publications

Purification, characterization, and directed evolution study of a vitamin D3 hydroxylase from Pseudonocardia autotrophica.

Putative helix F contributes to regioselectivity of hydroxylation in mitochondrial cytochrome P450 27A1.

Characterization of human sterol 27-hydroxylase. A mitochondrial cytochrome P-450 that catalyzes multiple oxidation reaction in bile acid biosynthesis.

Sterol 27-hydroxylase in bile acid biosynthesis. Mechanism of oxidation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,27-tetrol into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid.

Activities of recombinant human cytochrome P450c27 (CYP27) which produce intermediates of alternative bile acid biosynthetic pathways.

Oxidation of 5 beta-cholestane-3 alpha,7 alpha, 12 alpha-triol into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid by cytochrome P-450(26) from rabbit liver mitochondria.

Cloning, structure, and expression of the mitochondrial cytochrome P-450 sterol 26-hydroxylase, a bile acid biosynthetic enzyme.

Hydroxylations in biosynthesis of bile acids. Isolation of a cytochrome P-450 from rabbit liver mitochondria catalyzing 26-hydroxylation of C27-steroids.

Comments