Continued from EC 1.14.13.1 to EC 1.14.13.50
EC 1.14.13.101 to EC 1.14.13.149
Accepted name: 6-oxocineole dehydrogenase
Reaction: 6-oxocineole + NADPH + H+ + O2 = 1,6,6-trimethyl-2,7-dioxabicyclo[3.2.2]nonan-3-one + NADP+ + H2O
Other name(s): 6-oxocineole oxygenase
Systematic name: 6-oxocineole,NADPH:oxygen oxidoreductase
Comments: The product undergoes non-enzymic cleavage and subsequent ring closure to form the lactone 4,5-dihydro-5,5-dimethyl-4-(3-oxobutyl)furan-2(3H)-one.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 122933-80-6
References:
1. Williams, D.R., Trudgill, P.W. and Taylor, D.G. Metabolism of 1,8-cineole by a Rhodococcus species - ring cleavage reactions. J. Gen. Microbiol. 135 (1989) 1957-1967.
Accepted name: isoflavone 3'-hydroxylase
Reaction: formononetin + NADPH + H+ + O2 = calycosin + NADP+ + H2O
For diagram click here.
Other name(s): isoflavone 3'-monooxygenase
Systematic name: formononetin,NADPH:oxygen oxidoreductase (3'-hydroxylating)
Comments: A heme-thiolate protein (P-450). Also acts on biochanin A and other isoflavones with a 4'-methoxy group. Involved in the biosynthesis of the pterocarpin phytoalexins medicarpin and maackiain.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 110183-50-1
References:
1. Hinderer, W., Flentje, U. and Barz, W. Microsomal isoflavone 2'-hydroxylases and 3'-hydroxylases from chickpea (Cicer arietinum L) cell-suspensions induced for pterocarpan phytoalexin formation. FEBS Lett. 214 (1987) 101-106.
Accepted name: 4'-methoxyisoflavone 2'-hydroxylase
Reaction: formononetin + NADPH + H+ + O2 = 2'-hydroxyformononetin + NADP+ + H2O
For diagram click here.
Other name(s): isoflavone 2'-monooxygenase (ambiguous); isoflavone 2'-hydroxylase (ambiguous)
Systematic name: formononetin,NADPH:oxygen oxidoreductase (2'-hydroxylating)
Comments: A heme-thiolate protein (P-450). Acts on isoflavones with a 4'-methoxy group, such as formononetin and biochanin A. Involved in the biosynthesis of the pterocarpin phytoalexins medicarpin and maackiain. EC 1.14.13.89, isoflavone 2'-hydroxylase, is less specific and acts on other isoflavones as well as 4'-methoxyisoflavones.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 110183-49-8
References:
1. Hinderer, W., Flentje, U. and Barz, W. Microsomal isoflavone 2'-hydroxylases and 3'-hydroxylases from chickpea (Cicer arietinum L) cell-suspensions induced for pterocarpan phytoalexin formation. FEBS Lett. 214 (1987) 101-106.
Accepted name: ketosteroid monooxygenase
Reaction: a ketosteroid + NADPH + H+ + O2 = a steroid ester/lactone + NADP+ + H2O (general reaction)
(1) progesterone + NADPH + H+ + O2 = testosterone acetate + NADP+ + H2O
(2) androstenedione + NADPH + H+ + O2 = testololactone + NADP+ + H2O
(3) 17α-hydroxyprogesterone + NADPH + H+ + O2 = androstenedione + acetate + NADP+ + H2O
Glossary: progesterone = pregn-4-ene-3,20-dione
testosterone acetate = 3-oxoandrost-4-en-17β-yl acetate
androstenedione = androst-4-ene-3,17-dione
testololactone = 3-oxo-13,17-secoandrost-4-eno-17,13α-lactone
17α-hydroxyprogesterone = 17α-hydroxypregn-4-ene-3,20-dione
Other name(s): steroid-ketone monooxygenase; progesterone, NADPH2:oxygen oxidoreductase (20-hydroxylating, ester-producing); 17α-hydroxyprogesterone, NADPH2:oxygen oxidoreductase (20-hydroxylating, side-chain cleaving); androstenedione, NADPH2:oxygen oxidoreductase (17-hydroxylating, lactonizing)
Systematic name: ketosteroid,NADPH:oxygen oxidoreductase (20-hydroxylating, ester-producing/20-hydroxylating, side-chain cleaving/17-hydroxylating, lactonizing)
Comments: A single FAD-containing enzyme catalyses three types of monooxygenase (Baeyer-Villiger oxidation) reaction. The oxidative esterification of a number of derivatives of progesterone to produce the corresponding 17α-hydroxysteroid 17-acetate ester, such as testosterone acetate, is shown in Reaction (1). The oxidative lactonization of a number of derivatives of androstenedione to produce the 13,17-secoandrosteno-17,13α-lactone, such as testololactone, is shown in Reaction (2). The oxidative cleavage of the 17β-side-chain of 17α-hydroxyprogesterone to produce androstenedione and acetate is shown in Reaction (3). Reaction (1) is also catalysed by EC 1.14.99.4 (progesterone monooxygenase), and Reactions (2) and (3) correspond to that catalysed by EC 1.14.99.12 (androst-4-ene-3,17-dione monooxygenase). The possibility that a single enzyme is responsible for the reactions ascribed to EC 1.14.99.4 and EC 1.14.99.12 in other tissues cannot be excluded.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 9044-53-5
References:
1. Katagiri, M. and Itagaki, E. A steroid ketone monooxygenase from Cylindrocarpon radicicola. in Chemistry and Biochemistry of Flavoenzymes, (Müller, F., ed.) (1991) pp. 102-108, CRC Press, Florida.
2. Itagaki, E. Studies on a steroid monooxygenase from Cylindrocarpon radicicola ATCC 11011. Purification and characterization. J. Biochem. (Tokyo) 99 (1986) 815-824. [PMID: 3486863]
3. Itagaki, E. Studies on a steroid monooxygenase from Cylindrocarpon radicicola ATCC11011. Oxygenative lactonization of androstenedione to testololactone. J. Biochem. (Tokyo) 99 (1986) 825-832. [PMID: 3486864]
Accepted name: protopine 6-monooxygenase
Reaction: protopine + NADPH + H+ + O2 = 6-hydroxyprotopine + NADP+ + H2O
For diagram click here.
Other name(s): protopine 6-hydroxylase
Systematic name: protopine,NADPH:oxygen oxidoreductase (6-hydroxylating)
Comments: a heme-thiolate protein (P-450) involved in benzophenanthridine alkaloid synthesis in higher plants.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 128561-60-4
References:
1. Tanahashi, T. and Zenk, M.H. Elicitor induction and characterization of microsomal protopine-6-hydroxylase, the central enzyme in benzophenanthridine alkaloid biosynthesis. Phytochemistry 29 (1990) 1113-1122.
Accepted name: dihydrosanguinarine 10-monooxygenase
Reaction: dihydrosanguinarine + NADPH + H+ + O2 = 10-hydroxydihydrosanguinarine + NADP+ + H2O
For diagram click here.
Other name(s): dihydrosanguinarine 10-hydroxylase
Systematic name: dihydrosanguinarine,NADPH:oxygen oxidoreductase (10-hydroxylating)
Comments: a heme-thiolate protein (P-450) involved in benzophenanthridine alkaloid synthesis in higher plants.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 144388-41-0
References:
1. De-Eknamkul, W., Tanahashi, T. and Zenk, M.H. Enzymic 10-hydroxylation and 10-O-methylation of dihydrosanguinarine in dihydrochelirubine formation by Eschscholtzia. Phytochemistry 31 (1992) 2713-2717.
Accepted name: dihydrochelirubine 12-monooxygenase
Reaction:dihydrochelirubine + NADPH + H+ + O2 = 12-hydroxydihydrochelirubine + NADP+ + H2O
For diagram click here.
Other name(s): dihydrochelirubine 12-hydroxylase
Systematic name: dihydrochelirubine,NADPH:oxygen oxidoreductase (12-hydroxylating)
Comments: a heme-thiolate protein (P-450)
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 158736-41-5
References:
1. Kammerer, L., De-Eknamkul, W. and Zenk, M.H. Enzymic 12-hydroxylation and 12-O-methylation of dihydrochelirubine in dihydromacarpine formation by Thalictrum bulgaricum. Phytochemistry 36 (1994) 1409-1416.
Accepted name: benzoyl-CoA 3-monooxygenase
Reaction: benzoyl-CoA + NADPH + H+ + O2 = 3-hydroxybenzoyl-CoA + NADP+ + H2O
Other name(s): benzoyl-CoA 3-hydroxylase
Systematic name: benzoyl-CoA,NADPH:oxygen oxidoreductase (3-hydroxylating)
Comments: the enzyme from the denitrifying bacterium Pseudomonas KB740 catalyses a flavin-requiring reaction (FAD or FMN). Benzoate is not a substrate.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 151616-61-4
References:
1. Niemetz, R., Altenschmidt, U., Herrmann, H. and Fuchs, G. Benzoyl-coenzyme-A 3-monooxygenase, a flavin-dependent hydroxylase. Purification, some properties and its role in aerobic benzoate oxidation via gentisate in a denitrifying bacterium. Eur. J. Biochem. 227 (1995) 161-168. [PMID: 7851381]
Accepted name: L-lysine 6-monooxygenase (NADPH)
Reaction: L-lysine + NADPH + H+ + O2 = N6-hydroxy-L-lysine + NADP+ + H2O
Other name(s): lysine N6-hydroxylase
Systematic name: L-lysine,NADPH:oxygen oxidoreductase (6-hydroxylating)
Comments: A flavoprotein (FAD). The enzyme from strain EN 222 of Escherichia coli is highly specific for L-lysine; L-ornithine and L-homolysine are, for example, not substrates.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 64295-82-5
References:
1. Plattner, H.J., Pfefferle, P., Romaguera, A., Waschutza, S. and Diekmann, H. Isolation and some properties of lysine N6-hydroxylase from Escherichia coli strain EN222. Biol. Met. 2 (1989) 1-5. [PMID: 2518519]
2. Macheroux, P., Plattner, H.J., Romaguera, A. and Diekmann, H. FAD and substrate analogs as probes for lysine N6-hydroxylase from Escherichia coli EN 222. Eur. J. Biochem. 213 (1993) 995-1002. [PMID: 8504838]
3. Thariath, A.M., Fatum, K.L., Valvano, M.A. and Viswanatha, T. Physico-chemical characterization of a recombinant cytoplasmic form of lysine: N6-hydroxylase. Biochim. Biophys. Acta 1203 (1993) 27-35. [PMID: 8218389]
4. De Lorenzo, V., Bindereif, A., Paw, B.H. and Neilands, J.B. Aerobactin biosynthesis and transport genes of plasmid ColV-K30 in Escherichia coli K-12. J. Bacteriol. 165 (1986) 570-578. [PMID: 2935523]
5. Marrone, L., Siemann, S., Beecroft, M. and Viswanatha, T. Specificity of lysine:N-6-hydroxylase: A hypothesis for a reactive substrate intermediate in the catalytic mechanism. Bioorg. Chem. 24 (1996) 401-406.
6. Goh, C.J., Szczepan, E.W., Menhart, N. and Viswanatha, T. Studies on lysine: N6-hydroxylation by cell-free system of Aerobacter aerogenes 62-1. Biochim. Biophys. Acta 990 (1989) 240-245. [PMID: 2493814]
Accepted name: 27-hydroxycholesterol 7α-monooxygenase
Reaction: 27-hydroxycholesterol + NADPH + H+ + O2 = 7α,27-dihydroxycholesterol + NADP+ + H2O
For diagram click here.
Other name(s): 27-hydroxycholesterol 7α-hydroxylase
Systematic name: 27-hydroxycholesterol,NADPH:oxygen oxidoreductase (7α-hydroxylating)
Comments: a heme-thiolate protein (P-450). The enzyme from mammalian liver differs from cholesterol 7α-monooxygenase (EC 1.14.13.17) in having no activity towards cholesterol.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 149316-80-3
References:
1. Kumiko, O.M., Budai, K. and Javitt, N.B. Cholesterol and 27-hydroxycholesterol 7α-hydroxylation: evidence for two different enzymes. J. Lipid Res. 34 (1993) 581-588.
Accepted name: 2-hydroxyquinoline 8-monooxygenase
Reaction: quinolin-2-ol + NADH + H+ + O2 = quinolin-2,8-diol + NAD+ + H2O
Other name(s): 2-oxo-1,2-dihydroquinoline 8-monooxygenase
Systematic name: quinolin-2(1H)-one, NADH:oxygen oxidoreductase (8-oxygenating)
Comments: requires iron. Quinolin-2-ol exists largely as the quinolin-2(1H)-one tautomer.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 166799-89-9
References:
1. Rosche, B., Tshisuaka, B., Fetzner, S. and Lingens, F. 2-Oxo-1,2-dihydroquinoline 8-monooxygenase, a two-component enzyme system from Pseudomonas putida 86. J. Biol. Chem. 270 (1995) 17836-17842. [PMID: 7629085]
Accepted name: 4-hydroxyquinoline 3-monooxygenase
Reaction: quinolin-4-ol + NADH + H+ + O2 = quinolin-3,4-diol + NAD+ + H2O
Other name(s): quinolin-4(1H)-one 3-monooxygenase
Systematic name: quinolin-4(1H)-one,NADH:oxygen oxidoreductase (3-oxygenating)
Comments: quinolin-4-ol exists largely as the quinolin-4(1H)-one tautomer.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 144378-37-0
References:
1. Block, D.W. and Lingens, F. Microbial metabolism of quinoline and related compounds. XIV. Purification and properties of 1H-3-hydroxy-4-oxoquinoline oxygenase, a new estradiol cleavage enzyme from Pseudomonas putida strain 33/1. Biol. Chem. Hoppe Seyler 373 (1992) 249-254. [PMID: 1627263]
Accepted name: 3-hydroxyphenylacetate 6-hydroxylase
Reaction: 3-hydroxyphenylacetate + NAD(P)H + H+ + O2 = 2,5-dihydroxyphenylacetate + NAD(P)+ + H2O
Glossary: homogentisate = 2,5-dihydroxyphenylacetate
Other name(s): 3-hydroxyphenylacetate 6-monooxygenase
Systematic name: 3-hydroxyphenylacetate,NAD(P)H:oxygen oxidoreductase (6-hydroxylating)
Comments: 3-hydroxyphenylacetate 6-hydroxylase from Flavobacterium sp. is highly specific for 3-hydroxyphenylacetate and uses NADH and NADPH as electron donors with similar efficiency.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 114705-01-0
References:
1. van Berkel, W.H.J. and van den Tweel, W.J.J. Purification and characterisation of 3-hydroxyphenylacetate 6-hydroxylase: a novel FAD-dependent monooxygenase from a Flavobacterium sp. Eur. J. Biochem. 201 (1991) 585-592. [PMID: 1935954]
Accepted name: 4-hydroxybenzoate 1-hydroxylase
Reaction: 4-hydroxybenzoate + NAD(P)H + 2 H+ + O2 = hydroquinone + NAD(P)+ + H2O + CO2
Other name(s): 4-hydroxybenzoate 1-monooxygenase
Systematic name: 4-hydroxybenzoate,NAD(P)H:oxygen oxidoreductase (1-hydroxylating, decarboxylating)
Comments: requires FAD. The enzyme from Candida parapsilosis is specific for 4-hydroxybenzoate derivatives and prefers NADH to NADPH as electron donor.
Links to other databases: BRENDA, EXPASY, KEGG, UM-BBD , CAS registry number: 134214-78-1
References:
1. van Berkel, W.J.H., Eppink, M.H.M., Middelhoven, W.J., Vervoort, J. and Rietjens, I.M.C.M. Catabolism of 4-hydroxybenzoate in Candida parapsilosis proceeds through initial oxidative decarboxylation by a FAD-dependent 4-hydroxybenzoate 1-hydroxylase. FEMS Microbiol. Lett. 121 (1994) 207-216. [PMID: 7926672]
[EC 1.14.13.65 Deleted entry: 2-hydroxyquinoline 8-monooxygenase (EC 1.14.13.65 created 1999, deleted 2006)]
Accepted name: 2-hydroxycyclohexanone 2-monooxygenase
Reaction: 2-hydroxycyclohexan-1-one + NADPH + H+ + O2 = 6-hydroxyhexan-6-olide + NADP+ + H2O
Systematic name: 2-hydroxycyclohexan-1-one,NADPH:oxygen 2-oxidoreductase (1,2-lactonizing)
Comment: the product decomposes spontaneously to 6-oxohexanoic acid (adipic semialdehyde).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 62628-31-3
References
1. Davey, J.F. and Trudgill, P.W. The metabolism of trans-cyclohexan-1,2-diol by an Acinetobacter species. Eur. J. Biochem. 74 (1977) 115-127. [PMID: 856571]
Accepted name: quinine 3-monooxygenase
Reaction: quinine + NADPH + H+ + O2 = 3-hydroxyquinine + NADP+ + H2O
Glossary entries:
Quinine: a quinoline alkaloid
Other name(s): quinine 3-hydroxylase
Systematic name: quinine,NADPH:oxygen oxidoreductase
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Relling, M.V., Evans, R., Dass, C., Desiderio, D.M. and Nemec, J. Human cytochrome P450 metabolism of teniposide and etoposide. J. Pharmacol. Exp. Ther. 261 (1992) 491-496. [PMID: 1578365]
2. Zhang, H., Coville, P.F., Walker, R.J., Miners, J.O., Birkett, D.J. and Wanwimolruk, S. Evidence for involvement of human CYP3A in the 3-hydroxylation of quinine. Br. J. Clin. Pharmacol. 43 (1997) 245-252. [PMID: 9088578]
3. Zhao, X.-J., Kawashiro, T. and Ishizaki, T. Mutual inhibition between quinine and etoposide by human liver microsomes. Evidence for cytochrome P4503A4 involvement in their major metabolic pathways. Drug Metab. Dispos. 26 (1998) 188-191. [PMID: 9456308]
4. Zhao, X.-J., Yokoyama, H., Chiba, K., Wanwimolruk, S. and Ishizaki, T. Identification of human cytochrome P450 isoforms involved in the 3-hydroxylation of quinine by human liver microsomes and nine recombinant human cytochromes P450. J. Pharmacol. Exp. Ther. 279 (1996) 1327-1334. [PMID: 8968357]
Accepted name: 4-hydroxyphenylacetaldehyde oxime monooxygenase
Reaction: (Z)-4-hydroxyphenylacetaldehyde oxime + NADPH + H+ + O2 = (S)-4-hydroxymandelonitrile + NADP+ + 2 H2O
For diagram click here.
Other name(s): 4-hydroxybenzeneacetaldehyde oxime monooxygenase; cytochrome P450II-dependent monooxygenase; NADPH-cytochrome P450 reductase (CYP71E1); CYP71E1; 4-hydroxyphenylacetaldehyde oxime,NADPH:oxygen oxidoreductase
Systematic name: (Z)-4-hydroxyphenylacetaldehyde oxime,NADPH:oxygen oxidoreductase
Comments: This enzyme is involved in the biosynthesis of the cyanogenic glucoside dhurrin in sorghum, along with EC 1.14.13.41, tyrosine N-monooxygenase and EC 2.4.1.85, cyanohydrin β-glucosyltransferase.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. MacFarlane, I.J., Lees, E.M. and Conn, E.E. The in vitro biosynthesis of dhurrin, the cyanogenic glycoside of Sorghum bicolor. J. Biol. Chem. 250 (1975) 4708-4713. [PMID: 237909]
2. Shimada, M. and Conn, E.E. The enzymatic conversion of p-hydroxyphenylacetaldoxime to p-hydroxymandelonitrile Arch. Biochem. Biophys. 180 (1977) 199-207. [PMID: 193443]
3. Busk, P.K. and Møller, B.L. Dhurrin synthesis in sorghum is regulated at the transcriptional level and induced by nitrogen fertilization in older plants. Plant Physiol. 129 (2002) 1222-1231. [PMID: 12114576]
4. Kristensen, C., Morant, M., Olsen, C.E., Ekstrøm, C.T., Galbraith, D.W., Møller, B.L. and Bak, S. Metabolic engineering of dhurrin in transgenic Arabidopsis plants with marginal inadvertent effects on the metabolome and transcriptome. Proc. Natl. Acad. Sci. USA 102 (2005) 1779-1784. [PMID: 15665094]
Accepted name: alkene monooxygenase
Reaction: propene + NADH + H+ + O2 = 1,2-epoxypropane + NAD+ + H2O
For diagram click here.
Other name(s): alkene epoxygenase
Systematic name: alkene,NADH:oxygen oxidoreductase
Comments: The enzyme from Xanthobacter sp. strain Py2 is a multicomponent enzyme comprising (1) an NADH reductase, which provides the reductant for O2 activation; (2) a Rieske-type ferredoxin, which is an electron-transfer protein; (3) an oxygenase, which contains the catalytic centre for alkene epoxidation and (4) a small protein of unknown function that is essential for activity. Requires Fe(II). The enzyme oxygenates C2 to C6 aliphatic alkenes. With 1,2-epoxypropane as substrate, the stereospecifity of the epoxypropane formed is 95% (R) and 5% (S).
Links to other databases: BRENDA, EXPASY, KEGG, UM-BBD, CAS registry number: 63439-50-9
References:
1. Small, F.J. and Ensign, S.A. Alkene monooxygenase from Xanthobacter strain Py2: purification and characterization of a four-component system central to the bacterial metabolism of aliphatic alkenes. J. Biol. Chem. 272 (1997) 24913-24920. [PMID: 9312093]
2. Zhou, N.Y., Jenkins, A., Chion, C.K.N.C.K. and Leak, D.J. The alkene monooxygenase from Xanthobacter strain Py2 is closely related to aromatic monooxygenases and catalyzes aromatic monohydroxylation of benzene, toluene, and phenol. Appl. Environ. Microbiol. 65 (1999) 1589-1595. [PMID: 10103255]
3. Gallagher, S.C., Cammack, R. and Dalton, H. Alkene monooxygenase from Nocardia corallina B-276 is a member of the class of dinuclear iron proteins capable of stereospecific epoxygenation reactions. Eur. J. Biochem. 247 (1997) 635-641. [PMID: 9266707]
Accepted name: sterol 14-demethylase
Reaction: obtusifoliol + 3 O2 + 3 NADPH + 3 H+ = 4α-methyl-5α-ergosta-8,14,24(28)-trien-3β-ol + formate + 3 NADP+ + 4 H2O
For diagram click here.
Glossary:
obtusifoliol = 4α,14α-dimethyl-5α-ergosta-8,24(28)-dien-3β-ol or 4α,14α-dimethyl-24-methylene-5α-cholesta-8-en-3β-ol
Other name(s): obtusufoliol 14-demethylase; lanosterol 14-demethylase; lanosterol 14α-demethylase; sterol 14α-demethylase
Systematic name: sterol,NADPH:oxygen oxidoreductase (14-methyl cleaving)
Comments: The heme-thiolate enzyme (P-450) catalyses successive hydroxylations of the 14α-methyl group and C-15, followed by elimination as formate leaving the 14(15) double bond. This enzyme acts on a range of steroids with a 14α-methyl group.
Links to other databases: BRENDA, EXPASY, KEGG, PDB, CAS registry number: 60063-87-8
References:
1. Bak, S., Kahn, R.A., Olsen, C.E. and Halkier, B.A. Cloning and expression in Escherichia coli of the obtusifoliol 14α-demethylase of Sorghum bicolor (L.) Moench, a cytochrome P450 orthologous to the sterol 14α-demethylases (CYP51) from fungi and mammals. Plant J. 11 (1997) 191-201. [PMID: 9076987]
2. Aoyama, Y. and Yoshida, Y. Different substrate specificities of lanosterol 14α-demethylase (P450-14DM) of Saccharomyces cerevisiae and rat liver of 24-methylene-24,25-dihydrolanosterol and 24,25-dihydrolanosterol. Biochem. Biophys. Res. Commun. 178 (1991) 1064-1071. [PMID: 1872829]
3. Aoyama, Y. and Yoshida, Y. The 4β-methyl group of substrate does not affect the activity of lanosterol 14α-demethylase (P45014DM) of yeast: differences between the substrate recognition by yeast and plant sterol 14α-demethylases. Biochem. Biophys. Res. Commun. 183 (1992) 1266-1272. [PMID: 1567403]
4. Alexander, K., Akhtar, M., Boar, R.B., McGhie, J.F. and Barton, D.H.R. The removal of the 32-carbon atom as formic acid in cholesterol biosynthesis. J. Chem. Soc. Chem. Commun. (1972) 383-385.
Accepted name: N-methylcoclaurine 3'-monooxygenase
Reaction: (S)-N-methylcoclaurine + NADPH + H+ + O2 = (S)-3'-hydroxy-N-methylcoclaurine + NADP+ + H2O
For diagram click here.
Other name(s): N-methylcoclaurine 3'-hydroxylase
Systematic name: (S)-N-methylcoclaurine, NADPH:oxygen oxidoreductase (3'-hydroxylating)
Comments: A heme-thiolate protein (P-450) involved in benzylisoquinoline alkaloid synthesis in higher plants.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 202420-37-9
References:
1. Pauli, H.H. and Kutchan, T.M. Molecular cloning and functional heterologous expression of two alleles encoding (S)-N-methylcoclaurine 3'-hydroxylase (CYP80B1), a new methyl jasmonate-inducible cytochrome P-450-dependent mono-oxygenase of benzylisoquinoline alkaloid biosynthesis. Plant. J. 13 (1998) 793-801. [PMID: 9681018]
Accepted name: methylsterol monooxygenase
Reaction: 4,4-dimethyl-5α-cholest-7-en-3β-ol + 3 NAD(P)H + 3 H+ + 3 O2 = 3β-hydroxy-4β-methyl-5α-cholest-7-ene-4α-carboxylate + 3 NAD(P)+ + 4 H2O (overall reaction)
(1a) 4,4-dimethyl-5α-cholest-7-en-3β-ol + NAD(P)H + H+ + O2 = 4β-hydroxymethyl-4α-methyl-5α-cholest-7-en-3β-ol + NAD(P)+ + H2O
(1b) 4β-hydroxymethyl-4α-methyl-5α-cholest-7-en-3β-ol + NAD(P)H + H+ + O2 = 3β-hydroxy-4β-methyl-5α-cholest-7-ene-4α-carbaldehyde + NAD(P)+ + 2 H2O
(1c) 3β-hydroxy-4β-methyl-5α-cholest-7-ene-4α-carbaldehyde + NAD(P)H + H+ + O2 = 3β-hydroxy-4β-methyl-5α-cholest-7-ene-4α-carboxylate + NAD(P)+ + H2O
For diagram click here.
Other name(s): methylsterol hydroxylase; 4-methylsterol oxidase; 4,4-dimethyl-5α-cholest-7-en-3β-ol,hydrogen-donor:oxygen oxidoreductase (hydroxylating)
Systematic name: 4,4-dimethyl-5α-cholest-7-en-3β-ol,NAD(P)H:oxygen oxidoreductase (hydroxylating)
Comments: Requires cytochrome b5. Also acts on 4α-methyl-5α-cholest-7-en-3β-ol. The sterol can be based on cycloartenol as well as lanosterol. Formerly EC 1.14.99.16.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 37256-80-7
References:
1. Rahier, A., Smith, M. and Taton, M. The role of cytochrome b5 in 4α-methyl-oxidation and C5(6) desaturation of plant sterol precursors. Biochem. Biophys. Res. Commun. 236 (1997) 434-437. [PMID: 9240456]
2. Pascal, S., Taton, M. and Rahier, A. Plant sterol biosynthesis. Identification and characterization of two distinct microsomal oxidative enzymatic systems involved in sterol C4-demethylation. J. Biol. Chem. 268 (1993) 11639-11654. [PMID: 8505296 ]
3. Kawata, S., Trzaskos, J.M. and Gaylor, J.L. Affinity chromatography of microsomal enzymes on immobilized detergent-solubilized cytochrome b5. J. Biol. Chem. 261 (1986) 3790-3799. [PMID: 3949790 ]
4. Fukushima, H., Grinstead, G.F. and Gaylor, J.L. Total enzymic synthesis of cholesterol from lanosterol. Cytochrome b5-dependence of 4-methyl sterol oxidase. J. Biol. Chem. 256 (1981) 4822-4826. [PMID: 7228857 ]
5. Brady, D.R., Crowder, R.D. and Hayes, W.J. Mixed function oxidases in sterol metabolism. Source of reducing equivalents. J. Biol. Chem. 255 (1980) 10624-10629. [PMID: 7430141 ]
6. Gaylor, J.L. and Mason, H.S. Investigation of the component reactions of oxidative sterol demethylation. Evidence against participation of cytochrome P-450. J. Biol. Chem. 243 (1968) 4966-4972. [PMID: 4234469]
7. Miller, W.L., Kalafer, M.E., Gaylor, J.L. and Delwicke, C.V. Investigation of the component reactions of oxidative sterol demethylation. Study of the aerobic and anaerobic processes. Biochemistry 6 (1967) 2673-2678. [PMID: 4383278]
Accepted name: tabersonine 16-hydroxylase
Reaction: tabersonine + NADPH + H+ + O2 = 16-hydroxytabersonine + NADP+ + H2O
For diagram click here.
Other name(s): tabersonine-11-hydroxylase; T11H
Systematic name: tabersonine,NADPH:oxygen oxidoreductase (16-hydroxylating)
Comments: A heme-thiolate protein (P-450).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 250378-34-8
References:
1. St-Pierre, B. and De Luca, V. A cytochrome-P-450 monooxygenase catalyzes the first step in the conversion of tabersonine to vindoline in Catharanthus-roseus. Plant Physiol. 109 (1995) 131-139.
Accepted name: 7-deoxyloganin 7-hydroxylase
Reaction: 7-deoxyloganin + NADPH + H+ + O2 = loganin + NADP+ + H2O
For diagram click here.
Systematic name: 7-deoxyloganin,NADPH:oxygen oxidoreductase (7α-hydroxylating)
Comments: A heme-thiolate protein (P-450).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 335305-40-3
References:
1. Katano, N., Yamamoto, H., Iio, R. and Inoue, K. 7-Deoxyloganin 7-hydroxylase in Lonicera japonica cell cultures Phytochemistry 58 (2001) 53-58. [PMID: 11524113]
Accepted name: vinorine hydroxylase
Reaction: vinorine + NADPH + H+ + O2 = vomilenine + NADP+ + H2O
For diagram click here.
Systematic name: vinorine,NADPH:oxygen oxidoreductase (21α-hydroxylating)
Comments: A heme-thiolate protein (P-450). Forms a stage in the biosynthesis of the indole alkaloid ajmaline.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 162875-03-8
References:
1. Falkenhagen, H. and Stöckligt, J. Enzymatic biosynthesis of vomilenine, a key intermediate of the ajmaline pathway, catalysed by a novel cytochrome P-450-dependent enzyme from plant cell cultures of Rauwolfia serpentina. Z. Naturforsch. C: Biosci. 50 (1995) 45-53.
Accepted name: taxane 10β-hydroxylase
Reaction: taxa-4(20),11-dien-5α-yl acetate + NADPH + H+ + O2 = 10β-hydroxytaxa-4(20),11-dien-5α-yl acetate+ NADP+ + H2O
For diagram click here.
Systematic name: taxa-4(20),11-dien-5α-yl acetate,NADPH:oxygen oxidoreductase (10β-hydroxylating)
Comments: This microsomal cytochrome-P450-dependent enzyme is involved in the biosynthesis of the diterpenoid antineoplastic drug taxol (paclitaxel).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 337514-75-7
References:
1. Wheeler, A.L., Long, R.M., Ketchum, R.E., Rithner, C.D., Williams, R.M. and Croteau, R. Taxol biosynthesis: differential transformations of taxadien-5α-ol and its acetate ester by cytochrome P450 hydroxylases from Taxus suspension cells. Arch. Biochem. Biophys. 390 (2001) 265-78. [PMID: 11396929]
2. Jennewein, S., Rithner, C.D., Williams, R.M. and Croteau, R.B. Taxol biosynthesis: taxane 13 α-hydroxylase is a cytochrome P450-dependent monooxygenase. Proc. Natl. Acad. Sci. U S A 98 (2001) 13595-135600. [PMID: 11707604]
3. Schoendorf, A., Rithner, C.D., Williams, R.M. and Croteau, R.B. Molecular cloning of a cytochrome P450 taxane 10β-hydroxylase cDNA from Taxus and functional expression in yeast. Proc. Natl. Acad. Sci. USA 98 (2001) 1501-1506. [PMID: 11171980]
Accepted name: taxane 13α-hydroxylase
Reaction: taxa-4(20),11-dien-5α-ol + NADPH + H+ + O2 = taxa-4(20),11-dien-5α,13α-diol + NADP+ + H2O
For diagram click here.
Systematic name: taxa-4(20),11-dien-5α-ol,NADPH:oxygen oxidoreductase (13α-hydroxylating)
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 399030-58-1
References:
1. Wheeler, A.L., Long, R.M., Ketchum, R.E., Rithner, C.D., Williams, R.M. and Croteau, R. Taxol biosynthesis: differential transformations of taxadien-5α-ol and its acetate ester by cytochrome P450 hydroxylases from Taxus suspension cells. Arch. Biochem. Biophys. 390 (2001) 265-78. [PMID: 11396929]
2. Jennewein, S., Rithner, C.D., Williams, R.M. and Croteau, R.B. Taxol biosynthesis: taxane 13 α-hydroxylase is a cytochrome P450-dependent monooxygenase. Proc. Natl. Acad. Sci. U S A 98 (2001) 13595-135600. [PMID: 11707604]
Accepted name: ent-kaurene oxidase
Reaction: (1a) ent-kaur-16-ene + NADPH + H+ + O2 = ent-kaur-16-en-19-ol + NADP+ + H2O
(1b) ent-kaur-16-en-19-ol + NADPH + H+ + O2 = ent-kaur-16-en-19-al + NADP+ + 2 H2O
(1c) ent-kaur-16-en-19-al + NADPH + O2 = ent-kaur-16-en-19-oate + NADP+ + H2O
For diagram click here.
Systematic name: ent-kaur-16-ene,NADPH:oxygen oxidoreductase (hydroxylating)
Comments: Requires cytochrome P450. Catalyses three sucessive oxidations of the 4-methyl group of ent-kaurene giving kaurenoic acid.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 149565-67-3
References:
1. Ashman, P.J., Mackenzie, A. and Bramley, P.M. Characterization of ent-kaurene oxidase activity from Gibberella fujikuroi. Biochim. Biophys. Acta 1036 (1990) 151-157. [PMID: 2223832]
2. Archer, C., Ashman, P.J., Hedden, P., Bowyer, J.R. and Bramley, P.M. Purification of ent-kaurene oxidase from Gibberella fujikuroi and Cucurbita maxima. Biochem. Soc. Trans. 20 (1992) 218S only. [PMID: 1397591]
3. Helliwell, C.A., Poole, A., Peacock, W.J. and Dennis, E.S. Arabidopsis ent-kaurene oxidase catalyzes three steps of gibberellin biosynthesis. Plant Physiol. 119 (1999) 507-510. [PMID: 9952446]
Accepted name: ent-kaurenoic acid oxidase
Reaction: ent-kaur-16-en-19-oate + 3 NADPH + 3 H+ + 3 O2 = gibberellin A12 + 3 NADP+ + 4 H2O (overall reaction)
(1a) ent-kaur-16-en-19-oate + NADPH + H+ + O2 = ent-7α-hydroxykaur-16-en-19-oate + NADP+ + H2O
(1b) ent-7α-hydroxykaur-16-en-19-oate + NADPH + H+ + O2 = gibberellin A12 aldehyde + NADP+ + 2 H2O
(1c) gibberellin A12 aldehyde + NADPH + O2 = gibberellin A12 + NADP+ + H2O
For diagram click here.
Systematic name: ent-kaur-16-en-19-oate,NADPH:oxygen oxidoreductase (hydroxylating)
Comments: Requires cytochrome P450. Catalyses three sucessive oxidations of ent-kaurenoic acid. The second step includes a ring-B contraction giving the gibbane skeleton. In pumpkin (Cucurbita maxima) ent-6α,7α-dihydroxykaur-16-en-19-oate is also formed.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 337507-95-6
References:
1. Helliwell, C.A., Chandler, P.M., Poole, A., Dennis, E.S. and Peacock, W.J. The CYP88A cytochrome P450, ent-kaurenoic acid oxidase, catalyzes three steps of the gibberellin biosynthesis pathway. Proc. Natl. Acad. Sci. USA 98 (2001) 2065-2070. [PMID: 11172076]
Accepted name: (R)-limonene 6-monooxygenase
Reaction: (R)-limonene + NADPH + H+ + O2 = (+)-trans-carveol + NADP+ + H2O
For diagram click here.
Glossary: limonene = a monoterpenoid
(R)-limonene = (+)-limonene
Other name(s): (+)-limonene-6-hydroxylase; (+)-limonene 6-monooxygenase
Systematic name: (R)-limonene,NADPH:oxygen oxidoreductase (6-hydroxylating)
Comments: The reaction is stereospecific with over 95% yield of (+)-trans-carveol from (R)-limonene. (S)-Limonene, the substrate for EC 1.14.13.48, (S)-limonene 6-monooxygenase, is not a substrate. Forms part of the carvone biosynthesis pathway in Carum carvi (caraway) seeds.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 221461-49-0
References:
1. Bouwmeester, H.J., Gershenzon, J., Konings, M.C.J.M. and Croteau, R. Biosynthesis of the monoterpenes limonene and carvone in the fruit of caraway. I. Demonstration of enzyme activities and their changes with development. Plant Physiol. 117 (1998) 901-912. [PMID: 9662532]
2. Bouwmeester, H.J., Konings, M.C.J.M., Gershenzon, J., Karp, F. and Croteau, R. Cytochrome P-450 dependent (+)-limonene-6-hydroxylation in fruits of caraway (Carum Carvi). Phytochemistry 50 (1999) 243-248.
Accepted name: magnesium-protoporphyrin IX monomethyl ester (oxidative) cyclase
Reaction: magnesium-protoporphyrin IX 13-monomethyl ester + 3 NADPH + 3 H+ + 3 O2 = divinylprotochlorophyllide + 3 NADP+ + 5 H2O (overall reaction)
(1a) magnesium-protoporphyrin IX 13-monomethyl ester + NADPH + H+ + O2 = 131-hydroxy-magnesium-protoporphyrin IX 13-monomethyl ester + NADP+ + H2O
(1b) 131-hydroxy-magnesium-protoporphyrin IX 13-monomethyl ester + NADPH + H+ + O2 = 131-oxo-magnesium-protoporphyrin IX 13-monomethyl ester + NADP+ + 2 H2O
(1c) 131-oxo-magnesium-protoporphyrin IX 13-monomethyl ester + NADPH + H+ + O2 = divinylprotochlorophyllide + NADP+ + 2 H2O
For diagram of reaction click here (chlorophyll biosynthesis).
Other name(s): Mg-protoporphyrin IX monomethyl ester (oxidative) cyclase
Systematic name: magnesium-protoporphyrin-IX 13-monomethyl ester,NADPH:oxygen oxidoreductase (hydroxylating)
Comments: Requires Fe(II) for activity. The cyclase activity in Chlamydomonas reinhardtii is associated exclusively with the membranes, whereas that from cucumber cotyledons requires both membrane and soluble fractions for activity.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 92353-62-3
References:
1. Bollivar, D.W. and Beale, S.I. The chlorophyll biosynthetic enzyme Mg-protoporphyrin IX monomethyl ester (oxidative) cyclase (characterization and partial purification from Chlamydomonas reinhardtii and Synechocystis sp. PCC 6803). Plant Physiol. 112 (1996) 105-114. [PMID: 12226378]
Accepted name: vanillate monooxygenase
Reaction: vanillate + O2 + NADH + H+ = 3,4-dihydroxybenzoate + NAD+ + H2O + formaldehyde
For diagram of reaction click here
Glossary entries: vanillate = 4-hydroxy-3-methoxybenzoate
Other name(s): 4-hydroxy-3-methoxybenzoate demethylase; vanillate demethylase
Systematic name: vanillate:oxygen oxidoreductase (demethylating)
Comments: Forms part of the vanillin degradation pathway in Arthrobacter sp.
Links to other databases: BRENDA, EXPASY, KEGG, UM-BBD, CAS registry number: 39307-11-4
References:
1. Brunel, F. and Davison, J. Cloning and sequencing of Pseudomonas genes encoding vanillate demethylase. J. Bacteriol. 170 (1988) 4924-4930. [PMID: 3170489]
2. Priefert, H., Rabenhorst, J. and Steinbuchel, A. Molecular characterization of genes of Pseudomonas sp. strain HR199 involved in bioconversion of vanillin to protocatechuate. J. Bacteriol. 179 (1997) 2595-2607. [PMID: 9098058]
Accepted name: precorrin-3B synthase
Reaction: precorrin-3A + NADH + H+ + O2 = precorrin-3B + NAD+ + H2O
For diagram click here and mechanism here.
Other name(s): precorrin-3X synthase; CobG
Systematic name: precorrin-3A,NADH:oxygen oxidoreductase (20-hydroxylating)
Comments: An iron-sulfur protein. An oxygen atom from dioxygen is incorporated into the macrocycle at C-20. In the aerobic cobalamin biosythesis pathway, four enzymes are involved in the conversion of precorrin-3A to precorrin-6A. The first of the four steps is carried out by EC 1.14.13.83, precorrin-3B synthase (CobG), yielding precorrin-3B as the product. This is followed by three methylation reactions, which introduce a methyl group at C-17 (CobJ; EC 2.1.1.131), C-11 (CobM; EC 2.1.1.133) and C-1 (CobF; EC 2.1.1.152) of the macrocycle, giving rise to precorrin-4, precorrin-5 and precorrin-6A, respectively.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 152787-63-8
References:
1. Debussche, L., Thibaut, D., Cameron, B., Crouzet, J. and Blanche, F. Biosynthesis of the corrin macrocycle of coenzyme B12 in Pseudomonas denitrificans. J. Bacteriol. 175 (1993) 7430-7440. [PMID: 8226690]
2. Scott, A.I., Roessner, C.A., Stolowich, N.J., Spencer, J.B., Min, C. and Ozaki, S.I. Biosynthesis of vitamin B12. Discovery of the enzymes for oxidative ring contraction and insertion of the fourth methyl group. FEBS Lett. 331 (1993) 105-108. [PMID: 8405386]
3. Warren, M.J., Raux, E., Schubert, H.L. and Escalante-Semerena, J.C. The biosynthesis of adenosylcobalamin (vitamin B12). Nat. Prod. Rep. 19 (2002) 390-412. [PMID: 12195810]
Accepted name: 4-hydroxyacetophenone monooxygenase
Reaction: (4-hydroxyphenyl)ethan-1-one + NADPH + H+ + O2 = 4-hydroxyphenyl acetate + NADP+ + H2O
For diagram of reaction click here.
Other name(s): HAPMO
Systematic name: (4-hydroxyphenyl)ethan-1-one,NADPH:oxygen oxidoreductase (ester-forming)
Comments: Contains FAD. The enzyme from Pseudomonas fluorescens ACB catalyses the conversion of a wide range of acetophenone derivatives. Highest activity occurs with compounds bearing an electron-donating substituent at the para position of the aromatic ring [1]. In the absence of substrate, the enzyme can act as an NAD(P)H oxidase (EC 1.6.3.1).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 156621-13-5
References:
1. Kamerbeek, N.M., Moonen, M.J., van der Ven, J.G., van Berkel, W.J.H., Fraaije, M.W. and Janssen, D.B. 4-Hydroxyacetophenone monooxygenase from Pseudomonas fluorescens ACB: a novel flavoprotein catalyzing Baeyer-Villiger oxidation of aromatic compounds. Eur. J. Biochem. 268 (2001) 2547-2557. [PMID: 11322873 ]
2. Kamerbeek, N.M, Olsthoorn, A.J.J., Fraaije, M.W. and Janssen, D.B. Substrate specificity of a novel Baeyer-Villiger monooxygenase, 4-hydroxyacetophenone monooxygenase. Appl. Environ. Microbiol. 69 (2003) 419-426. [PMID: 12514023]
Accepted name: glyceollin synthase
Reaction: 2-(or 4-)dimethylallyl-(6aS,11aS)-3,6a,9-trihydroxypterocarpan + NADPH + H+ + O2 = glyceollin + NADP+ + 2 H2O
For diagram click here.
Other Name(s): dimethylallyl-3,6a,9-trihydroxypterocarpan cyclase
Systematic name: 2-(or 4-)dimethylallyl-(6aS,11aS)-3,6a,9-trihydroxypterocarpan,NADPH:oxygen oxidoreductase (cyclizing)
Comments: A heme-thiolate protein (P-450). Glyceollins II and III are formed from 2-dimethylallyl-(6aS,11aS)-3,6a,9-trihydroxypterocarpan whereas glyceollin I is formed from the 4-isomer.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Welle, R. and Grisebach, H. Induction of phytoalexin synthesis in soybean: enzymatic cyclization of prenylated pterocarpans to glyceollin isomers. Arch. Biochem. Biophys. 263 (1988) 191-198. [PMID: 3369863]
Accepted name: 2-hydroxyisoflavanone synthase
Reaction: apigenin + 2 NADPH + 2 H+ + O2 = 2-hydroxy-2,3-dihydrogenistein + 2 NADP+ + H2O
See diagram for reaction click here.
Other Name(s): 2-HIS
Systematic name: apigenin,NADPH:oxygen oxidoreductase (isoflavanone-forming)
Comments: A heme-thiolate protein (P-450). EC 4.2.1.105, 2-hydroxyisoflavanone dehydratase, acts on 2-hydroxy-2,3-dihydrogenistein with loss of water and formation of genistein. This may occur spontaneously.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 168680-18-0
References:
1. Kochs. G. and Grisebach, H. Enzymic synthesis of isoflavones. Eur. J. Biochem. 155 (1986) 311-318. [PMID: 3956488]
2. Steele, C. L., Gijzen, M., Qutob, D. and Dixon, R.A. Molecular characterization of the enzyme catalyzing the aryl migration reaction of isoflavonoid biosynthesis in soybean. Arch. Biochem. Biophys. 367 (1999) 146-150. [PMID: 10375412]
Accepted name: licodione synthase
Reaction: liquiritigenin + NADPH + H+ + O2 = licodione + NADP+ + H2O
For diagram click here.
Glossary: licodione = 1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)propane-1,3-dione
Systematic name: liquiritigenin,NADPH:oxygen oxidoreductase (licodione-forming)
Comments: A heme-thiolate protein (P-450). It probably forms 2-hydroxyliquiritigenin which spontaneously forms licodione. NADH can act instead of NADPH, but more slowly.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 157972-05-9
References:
1. Otani, K., Takahashi, T., Furuya, T. and Ayabe, S. Licodione synthase, a cytochrome P450 monooxygenase catalyzing 2-hydroxylation of 5-deoxyflavanone, in cultured Glycyrrhiza echinata L. cells. Plant Physiol. 105 (1994) 1427-1432. [PMID: 12232298]
2. Akashi, T., Aoki, T. and Ayabe, S. Identification of a cytochrome P450 cDNA encoding (2S)-flavanone 2-hydroxylase of licorice (Glycyrrhiza echinata L.; Fabaceae) which represents licodione synthase and flavone synthase II. FEBS Lett. 431 (1998) 287-290. [PMID: 9708921]
Accepted name: flavonoid 3',5'-hydroxylase
Reaction: a flavanone + 2 NADPH + 2 H+ + 2 O2 = a 3',5'-dihydroxyflavanone + 2 NADP+ + 2 H2O (overall reaction)
(1a) a flavanone + NADPH + H+ + O2 = a 3'-hydroxyflavanone + NADP+ + H2O
(1b) a 3'-hydroxyflavanone + NADPH + H+ + O2 = a 3',5'-dihydroxyflavanone + NADP+ + H2O
See diagram for reaction in ampelopsin or dihydrotricetin or taxifolin biosynthesis.
Other Name(s): F3'5'H; F3',5'H
Systematic name: flavanone,NADPH:oxygen oxidoreductase
Comments: A heme-thiolate protein (P-450). The 3',5'-dihydroxyflavanone is formed via the 3'-hydroxyflavanone. In Petunia hybrida the enzyme acts on naringenin, eriodictyol, dihydroquercetin (taxifolin) and dihydrokaempferol (aromadendrin). The enzyme catalyses the hydroxylation of 5,7,4'-trihydroxyflavanone (naringenin) at either the 3' position to form eriodictyol or at both the 3' and 5' positions to form 5,7,3',4',5'-pentahydroxyflavanone (dihydrotricetin). The enzyme also catalyses the hydroxylation of 3,5,7,3',4'-pentahydroxyflavanone (taxifolin) at the 5' position, forming ampelopsin. NADH is not a good substitute for NADPH.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 94047-23-1
References:
1. Menting, J., Scopes, R.K. and Stevenson, T.W. Characterization of flavonoid 3',5'-hydroxylase in microsomal membrane fraction of Petunia hybrida flowers. Plant Physiol. 106 (1994) 633-642. [PMID: 12232356]
2. Shimada, Y., Nakano-Shimada, R., Ohbayashi, M., Okinaka, Y., Kiyokawa, S. and Kikuchi, Y. Expression of chimeric P450 genes encoding flavonoid-3',5'-hydroxylase in transgenic tobacco and petunia plants. FEBS Lett. 461 (1999) 241-245. [PMID: 10567704]
3. de Vetten, N., ter Horst, J., van Schaik, H.P., de Boer, A., Mol, J. and Koes, R. A cytochrome b5 is required for full activity of flavonoid 3',5'-hydroxylase, a cytochrome P450 involved in the formation of blue flower colors. Proc. Natl. Acad. Sci. USA 96 (1999) 778-783. [PMID: 9892710]
Accepted name: isoflavone 2'-hydroxylase
Reaction: an isoflavone + NADPH + H+ + O2 = a 2'-hydroxyisoflavone + NADP+ + H2O
For diagram click here.
Other name(s): isoflavone 2'-monooxygenase; CYP81E1; CYP Ge-3
Systematic name: isoflavone,NADPH:oxygen oxidoreductase (2'-hydroxylating)
Comments: A heme-thiolate protein (P-450). Acts on daidzein, formononetin and genistein. EC 1.14.13.53, 4'-methoxyisoflavone 2'-hydroxylase, has the same reaction but is more specific as it requires a 4'-methoxyisoflavone.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 110183-49-8
References:
1. Akashi, T., Aoki, T. and Ayabe, S.-I. CYP81E1, a cytochrome P450 cDNA of licorice (Glycyrrhiza echinata L.), encodes isoflavone 2'-hydroxylase. Biochem. Biophys. Res. Commun. 251 (1998) 67-70. [PMID: 9790908]
Accepted name: zeaxanthin epoxidase
Reaction: zeaxanthin + 2 NAD(P)H + 2 H+ + 2 O2 = violaxanthin + 2 NAD(P)+ + 2 H2O (overall reaction)
(1a) zeaxanthin + NAD(P)H + H+ + O2 = antheraxanthin + NAD(P)+ + H2O
(1b) antheraxanthin + NAD(P)H + H+ + O2 = violaxanthin + NAD(P)+ + H2O
For diagram click here.
Other name(s): Zea-epoxidase
Systematic name: zeaxanthin,NAD(P)H:oxygen oxidoreductase
Comments: A flavoprotein (FAD) that is active under conditions of low light. Along with EC 1.10.99.3, violaxanthin de-epoxidase, this enzyme forms part of the xanthophyll (or violaxanthin) cycle, which is involved in protecting the plant against damage by excess light. It will also epoxidize lutein in some higher-plant species.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 149718-34-3
References:
1. Buch, K., Stransky, H. and Hager, A. FAD is a further essential cofactor of the NAD(P)H and O2-dependent zeaxanthin-epoxidase. FEBS Lett. 376 (1995) 45-48. [PMID: 8521963]
2. Bugos, R.C., Hieber, A.D. and Yamamoto, H.Y. Xanthophyll cycle enzymes are members of the lipocalin family, the first identified from plants. J. Biol. Chem. 273 (1998) 15321-15324. [PMID: 9624110]
3. Thompson, A.J., Jackson, A.C., Parker, R.A., Morpeth, D.R., Burbidge, A. and Taylor, I.B. Abscisic acid biosynthesis in tomato: regulation of zeaxanthin epoxidase and 9-cis-epoxycarotenoid dioxygenase mRNAs by light/dark cycles, water stress and abscisic acid. Plant Mol. Biol. 42 (2000) 833-845. [PMID: 10890531]
4. Hieber, A.D., Bugos, R.C. and Yamamoto, H.Y. Plant lipocalins: violaxanthin de-epoxidase and zeaxanthin epoxidase. Biochim. Biophys. Acta 1482 (2000) 84-91. [PMID: 11058750]
5. Frommolt, R., Goss, R. and Wilhelm, C. The de-epoxidase and epoxidase reactions of Mantoniella squamata (Prasinophyceae) exhibit different substrate-specific reaction kinetics compared to spinach. Planta 213 (2001) 446-456. [PMID: 11506368]
6. Frommolt, R., Goss, R. and Wilhelm, C. Erratum Report. The de-epoxidase and epoxidase reactions of Mantoniella squamata (Prasinophyceae) exhibit different substrate-specific reaction kinetics compared to spinach. Planta 213 (2001) 492. [PMID: 11506368]
7. Matsubara, S., Morosinotto, T., Bassi, R., Christian, A.L., Fischer-Schliebs, E., Luttge, U., Orthen, B., Franco, A.C., Scarano, F.R., Forster, B., Pogson, B.J. and Osmond, C.B. Occurrence of the lutein-epoxide cycle in mistletoes of the Loranthaceae and Viscaceae. Planta 217 (2003) 868-879. [PMID: 12844265]
Accepted name: deoxysarpagine hydroxylase
Reaction: 10-deoxysarpagine + NADPH + H+ + O2 = sarpagine + NADP+ + H2O
For diagram click here.
Other name(s): DOSH
Systematic name: 10-deoxysarpagine,NADPH:oxygen oxidoreductase (10-hydroxylating)
Comments: A heme-thiolate protein (P-450).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Yu, B., Ruppert, M. and Stöckigt, J. Deoxysarpagine hydroxylase — a novel enzyme closing a short side pathway of alkaloid biosynthesis in Rauvolfia. Bioorg. Med. Chem. 10 (2002) 2479-2483. [PMID: 12057637]
Accepted name: phenylacetone monooxygenase
Reaction: phenylacetone + NADPH + H+ + O2 = benzyl acetate + NADP+ + H2O
For diagram click here.
Other name(s): PAMO
Systematic name: phenylacetone,NADPH:oxygen oxidoreductase
Comments: A flavoprotein (FAD). NADH cannot replace NADPH as coenzyme. In addition to phenylacetone, which is the best substrate found to date, this Baeyer-Villiger monooxygenase can oxidize other aromatic ketones [1-(4-hydroxyphenyl)propan-2-one, 1-(4-hydroxyphenyl)propan-2-one and 3-phenylbutan-2-one], some alipatic ketones (e.g. dodecan-2-one) and sulfides (e.g. 1-methyl-4-(methylsulfanyl)benzene).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 1005768-90-0
References:
1. Malito, E., Alfieri, A., Fraaije, M.W. and Mattevi, A. Crystal structure of a Baeyer-Villiger monooxygenase. Proc. Natl. Acad. Sci. USA 101 (2004) 13157-13162. [PMID: 15328411]
2. Fraaije, M.W., Wu, J., Heuts, D.P., van Hellemond, E.W., Spelberg, J.H. and Janssen, D.B. Discovery of a thermostable Baeyer-Villiger monooxygenase by genome mining. Appl. Microbiol. Biotechnol. 66 (2005) 393-400. [PMID: 15599520]
Accepted name: (+)-abscisic acid 8'-hydroxylase
Reaction: (+)-abscisate + NADPH + H+ + O2 = 8'-hydroxyabscisate + NADP+ + H2O
For diagram click here.
Other name(s): (+)-ABA 8'-hydroxylase; ABA 8'-hydroxylase
Systematic name: abscisate,NADPH:oxygen oxidoreductase (8'-hydroxylating)
Comments: A heme-thiolate protein (P-450). Catalyses the first step in the oxidative degradation of abscisic acid and is considered to be the pivotal enzyme in controlling the rate of degradation of this plant hormone [1]. CO inhibits the reaction, but its effects can be reversed by the presence of blue light [1]. The 8'-hydroxyabscisate formed can be converted into (–)-phaseic acid, most probably spontaneously. Other enzymes involved in the abscisic-acid biosynthesis pathway are EC 1.1.1.288 (xanthoxin dehydrogenase), EC 1.2.3.14 (abscisic aldehyde oxidase) and EC 1.13.11.51 (9-cis-epoxycarotenoid dioxygenase).
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 153190-37-5
References:
1. Cutler, A.J., Squires, T.M., Loewen, M.K. and Balsevich, J.J. Induction of (+)-abscisic acid 8' hydroxylase by (+)-abscisic acid in cultured maize cells. J. Exp. Bot. 48 (1997) 1787-1795.
2. Krochko, J.E., Abrams, G.D., Loewen, M.K., Abrams, S.R. and Cutler, A.J. (+)-Abscisic acid 8'-hydroxylase is a cytochrome P450 monooxygenase. Plant Physiol. 118 (1998) 849-860. [PMID: 9808729]
Accepted name: lithocholate 6β-hydroxylase
Reaction: lithocholate + NADPH + H+ + O2 = 6β-hydroxylithocholate + NADP+ + H2O
For diagram click here.
Glossary: lithocholic acid = 3α-hydroxy-5β-cholan-24-oic acid
murideoxycholic acid = 3α,6β-dihydroxy-5β-cholan-24-oic acid
Other name(s): lithocholate 6β-monooxygenase; CYP3A10; 6β-hydroxylase; cytochrome P450 3A10/lithocholic acid 6β-hydroxylase
Systematic name: lithocholate,NADPH:oxygen oxidoreductase (6β-hydroxylating)
Comments: A heme-thiolate protein (P-450). Expression of the gene for this enzyme is 50-fold higher in male compared to female hamsters [1].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 9075-83-6
References:
1. Teixeira, J. and Gil, G. Cloning, expression, and regulation of lithocholic acid 6β-hydroxylase. J. Biol. Chem. 266 (1991) 21030-21036. [PMID: 1840595]
2. Chang, T.K., Teixeira, J., Gil, G. and Waxman, D.J. The lithocholic acid 6β-hydroxylase cytochrome P-450, CYP 3A10, is an active catalyst of steroid-hormone 6β-hydroxylation. Biochem. J. 291 (1993) 429-433. [PMID: 8484723]
3. Subramanian, A., Wang, J. and Gil, G. STAT 5 and NF-Y are involved in expression and growth hormone-mediated sexually dimorphic regulation of cytochrome P450 3A10/lithocholic acid 6β-hydroxylase. Nucleic Acids Res. 26 (1998) 2173-2178. [PMID: 9547277]
4. Russell, D.W. The enzymes, regulation, and genetics of bile acid synthesis. Annu. Rev. Biochem. 72 (2003) 137-174. [PMID: 12543708]
Accepted name: 7α-hydroxycholest-4-en-3-one 12α-hydroxylase
Reaction: 7α-hydroxycholest-4-en-3-one + NADPH + H+ + O2 = 7α,12α-dihydroxycholest-4-en-3-one + NADP+ + H2O
For diagram click here.
Other name(s): 7α-hydroxy-4-cholesten-3-one 12α-monooxygenase; CYP12; sterol 12α-hydroxylase (ambiguous); HCO 12α-hydroxylase
Systematic name: 7α-hydroxycholest-4-en-3-one,NADPH:oxygen oxidoreductase (12α-hydroxylating)
Comments: A heme-thiolate protein (P-450). Requires EC 1.6.2.4, NADPH—hemoprotein reductase and cytochrome b5 for maximal activity. This enzyme is important in bile acid biosynthesis, being responsible for the balance between the formation of cholic acid and chenodeoxycholic acid [2].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Ishida, H., Noshiro, M., Okuda, K. and Coon, M.J. Purification and characterization of 7α-hydroxy-4-cholesten-3-one 12α-hydroxylase. J. Biol. Chem. 267 (1992) 21319-21323. [PMID: 1400444]
2. Eggertsen, G., Olin, M., Andersson, U., Ishida, H., Kubota, S., Hellman, U., Okuda, K.I. and Björkhem, I. Molecular cloning and expression of rabbit sterol 12α-hydroxylase. J. Biol. Chem. 271 (1996) 32269-32275. [PMID: 8943286]
3. Russell, D.W. The enzymes, regulation, and genetics of bile acid synthesis. Annu. Rev. Biochem. 72 (2003) 137-174. [PMID: 12543708]
Accepted name: 5β-cholestane-3α,7α-diol 12α-hydroxylase
Reaction: 5β-cholestane-3α,7α-diol + NADPH + H+ + O2 = 5β-cholestane-3α,7α,12α-triol + NADP+ + H2O
For diagram click here.
Other name(s): 5β-cholestane-3α,7α-diol 12α-monooxygenase; sterol 12α-hydroxylase (ambiguous); CYP8B1; cytochrome P450 8B1
Systematic name: 5β-cholestane-3α,7α-diol,NADPH:oxygen oxidoreductase (12α-hydroxylating)
Comments: A heme-thiolate protein (P-450). This is the key enzyme in the biosynthesis of the bile acid cholic acid (3α,7α,12α-trihydroxy-5β-cholanoic acid). The activity of this enzyme determines the biosynthetic ratio between cholic acid and chenodeoxycholic acid [3]. The enzyme can also hydroxylate the substrate at the 25 and 26 position, but to a lesser extent [1].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Hansson, R. and Wikvall, K. Hydroxylations in biosynthesis of bile acids. Cytochrome P-450 LM4 and 12α-hydroxylation of 5β-cholestane-3α,7α-diol. Eur. J. Biochem. 125 (1982) 423-429. [PMID: 6811268]
2. Hansson, R. and Wikvall, K. Hydroxylations in biosynthesis and metabolism of bile acids. Catalytic properties of different forms of cytochrome P-450. J. Biol. Chem. 255 (1980) 1643-1649. [PMID: 6766451]
3. Lundell, K. and Wikvall, K. Gene structure of pig sterol 12α-hydroxylase (CYP8B1) and expression in fetal liver: comparison with expression of taurochenodeoxycholic acid 6α-hydroxylase (CYP4A21). Biochim. Biophys. Acta 1634 (2003) 86-96. [PMID: 14643796]
4. del Castillo-Olivares, A. and Gil, G. α1-Fetoprotein transcription factor is required for the expression of sterol 12α-hydroxylase, the specific enzyme for cholic acid synthesis. Potential role in the bile acid-mediated regulation of gene transcription. J. Biol. Chem. 275 (2000) 17793-17799. [PMID: 10747975]
5. Yang, Y., Zhang, M., Eggertsen, G. and Chiang, J.Y. On the mechanism of bile acid inhibition of rat sterol 12α-hydroxylase gene (CYP8B1) transcription: roles of α-fetoprotein transcription factor and hepatocyte nuclear factor 4α. Biochim. Biophys. Acta 1583 (2002) 63-73. [PMID: 12069850]
6. Russell, D.W. The enzymes, regulation, and genetics of bile acid synthesis. Annu. Rev. Biochem. 72 (2003) 137-174. [PMID: 12543708]
Accepted name: taurochenodeoxycholate 6α-hydroxylase
Reaction: (1) taurochenodeoxycholate + NADPH + H+ + O2 = taurohyocholate + NADP+ + H2O
(2) lithocholate + NADPH + H+ + O2 = hyodeoxycholate + NADP+ + H2O
For diagram click here.
Glossary: taurochenodeoxycholic acid = N-(3α,7α-dihydroxy-5β-cholan-24-oyl)taurine
taurohyocholic acid = N-(3α,6α,7α-trihydroxy-5β-cholan-24-oyl)taurine
hyodeoxycholate = 3α,6α-dihydroxy-5β-cholanoate
Other name(s): CYP3A4; CYP4A21; taurochenodeoxycholate 6α-monooxygenase
Systematic name: taurochenodeoxycholate,NADPH:oxygen oxidoreductase (6α-hydroxylating)
Comments: A heme-thiolate protein (P-450). Requires cytochrome b5 for maximal activity. Acts on taurochenodeoxycholate, taurodeoxycholate and less readily on lithocholate and chenodeoxycholate. In adult pig (Sus scrofa), hyocholic acid replaces cholic acid as a primary bile acid [5].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 105669-85-0
References:
1. Araya, Z. and Wikvall, K. 6α-Hydroxylation of taurochenodeoxycholic acid and lithocholic acid by CYP3A4 in human liver microsomes. Biochim. Biophys. Acta 1438 (1999) 47-54. [PMID: 10216279]
2. Araya, Z., Hellman, U. and Hansson, R. Characterisation of taurochenodeoxycholic acid 6α-hydroxylase from pig liver microsomes. Eur. J. Biochem. 231 (1995) 855-861. [PMID: 7649186]
3. Kramer, W., Sauber, K., Baringhaus, K.H., Kurz, M., Stengelin, S., Lange, G., Corsiero, D., Girbig, F., Konig, W. and Weyland, C. Identification of the bile acid-binding site of the ileal lipid-binding protein by photoaffinity labeling, matrix-assisted laser desorption ionization-mass spectrometry, and NMR structure. J. Biol. Chem. 276 (2001) 7291-7301. [PMID: 11069906]
4. Lundell, K., Hansson, R. and Wikvall, K. Cloning and expression of a pig liver taurochenodeoxycholic acid 6α-hydroxylase (CYP4A21): a novel member of the CYP4A subfamily. J. Biol. Chem. 276 (2001) 9606-9612. [PMID: 11113117]
5. Lundell, K. and Wikvall, K. Gene structure of pig sterol 12α-hydroxylase (CYP8B1) and expression in fetal liver: comparison with expression of taurochenodeoxycholic acid 6α-hydroxylase (CYP4A21). Biochim. Biophys. Acta 1634 (2003) 86-96. [PMID: 14643796]
6. Russell, D.W. The enzymes, regulation, and genetics of bile acid synthesis. Annu. Rev. Biochem. 72 (2003) 137-174. [PMID: 12543708]
Accepted name: cholesterol 24-hydroxylase
Reaction: cholesterol + NADPH + H+ + O2 = (24S)-24-hydroxycholesterol + NADP+ + H2O
For diagram click here.
Glossary: cholesterol = cholest-5-en-3β-ol
Other name(s): cholesterol 24-monooxygenase; CYP46; CYP46A1; cholesterol 24S-hydroxylase; cytochrome P450 46A1
Systematic name: cholesterol,NADPH:oxygen oxidoreductase (24-hydroxylating)
Comments: A heme-thiolate protein (P-450). The enzyme can also produce 25-hydroxycholesterol. In addition, it can further hydroxylate the product to 24,25-dihydroxycholesterol and 24,27-dihydroxycholesterol [2]. This reaction is the first step in the enzymatic degradation of cholesterol in the brain as hydroxycholesterol can pass the blood—brain barrier whereas cholesterol cannot [3].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 50812-30-1, 213327-78-7
References:
1. Lund, E.G., Guileyardo, J.M. and Russell, D.W. cDNA cloning of cholesterol 24-hydroxylase, a mediator of cholesterol homeostasis in the brain. Proc. Natl. Acad. Sci. USA 96 (1999) 7238-7243. [PMID: 10377398]
2. Mast, N., Norcross, R., Andersson, U., Shou, M., Nakayama, K., Bjorkhem, I. and Pikuleva, I.A. Broad substrate specificity of human cytochrome P450 46A1 which initiates cholesterol degradation in the brain. Biochemistry 42 (2003) 14284-14292. [PMID: 14640697]
3. Lund, E.G., Xie, C., Kotti, T., Turley, S.D., Dietschy, J.M. and Russell, D.W. Knockout of the cholesterol 24-hydroxylase gene in mice reveals a brain-specific mechanism of cholesterol turnover. J. Biol. Chem. 278 (2003) 22980-22988. [PMID: 12686551]
4. Bogdanovic, N., Bretillon, L., Lund, E.G., Diczfalusy, U., Lannfelt, L., Winblad, B., Russell, D.W. and Björkhem, I. On the turnover of brain cholesterol in patients with Alzheimer's disease. Abnormal induction of the cholesterol-catabolic enzyme CYP46 in glial cells. Neurosci. Lett. 314 (2001) 45-48. [PMID: 11698143]
5. Russell, D.W. The enzymes, regulation, and genetics of bile acid synthesis. Annu. Rev. Biochem. 72 (2003) 137-174. [PMID: 12543708]
Accepted name: 24-hydroxycholesterol 7α-hydroxylase
Reaction: (24R)-cholest-5-ene-3β,24-diol + NADPH + H+ + O2 = (24R)-cholest-5-ene-3β,7α,24-triol + NADP+ + H2O
For diagram click here.
Other name(s): 24-hydroxycholesterol 7α-monooxygenase; CYP39A1; CYP39A1 oxysterol 7α-hydroxylase
Systematic name: (24R)-cholest-5-ene-3β,24-diol,NADPH:oxygen oxidoreductase (7α-hydroxylating)
Comments: A heme-thiolate protein (P-450) that is found in liver microsomes and in ciliary non-pigmented epithelium [2]. The enzyme is specific for (24R)-cholest-5-ene-3β,24-diol as substrate.
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number: 288309-90-0
References:
1. Li-Hawkins, J., Lund, E.G., Bronson, A.D. and Russell, D.W. Expression cloning of an oxysterol 7α-hydroxylase selective for 24-hydroxycholesterol. J. Biol. Chem. 275 (2000) 16543-16549. [PMID: 10748047]
2. Ikeda, H., Ueda, M., Ikeda, M., Kobayashi, H. and Honda, Y. Oxysterol 7α-hydroxylase (CYP39A1) in the ciliary nonpigmented epithelium of bovine eye. Lab. Invest. 83 (2003) 349-355. [PMID: 12649335]
3. Russell, D.W. The enzymes, regulation, and genetics of bile acid synthesis. Annu. Rev. Biochem. 72 (2003) 137-174. [PMID: 12543708]
Accepted name: 25-hydroxycholesterol 7α-hydroxylase
Reaction: (1) cholest-5-ene-3β,25-diol + NADPH + H+ + O2 = cholest-5-ene-3β,7α,25-triol + NADP+ + H2O
(2) cholest-5-ene-3β,27-diol + NADPH + H+ + O2 = cholest-5-ene-3β,7α,27-triol + NADP+ + H2O
For diagram click here.
Other name(s): 25-hydroxycholesterol 7α-monooxygenase; CYP7B1; CYP7B1 oxysterol 7α-hydroxylase
Systematic name: cholest-5-ene-3β,25-diol,NADPH:oxygen oxidoreductase (7α-hydroxylating)
Comments: A heme-thiolate protein (P-450). Unlike EC 1.14.13.99, 24-hydroxycholesterol 7α-monooxygenase, which is specific for its oxysterol substrate, this enzyme can also metabolize the oxysterols 24,25-epoxycholesterol, 22-hydroxycholesterol and 24-hydroxycholesterol, but to a lesser extent [2].
Links to other databases: BRENDA, EXPASY, KEGG, CAS registry number:
References:
1. Toll, A., Wikvall, K., Sudjana-Sugiaman, E., Kondo, K.H. and Björkhem, I. 7α hydroxylation of 25-hydroxycholesterol in liver microsomes. Evidence that the enzyme involved is different from cholesterol 7α-hydroxylase. Eur. J. Biochem. 224 (1994) 309-316. [PMID: 7925343]
2. Li-Hawkins, J., Lund, E.G., Bronson, A.D. and Russell, D.W. Expression cloning of an oxysterol 7α-hydroxylase selective for 24-hydroxycholesterol. J. Biol. Chem. 275 (2000) 16543-16549. [PMID: 10748047]
3. Ren, S., Marques, D., Redford, K., Hylemon, P.B., Gil, G., Vlahcevic, Z.R. and Pandak, W.M. Regulation of oxysterol 7α-hydroxylase (CYP7B1) in the rat. Metabolism 52 (2003) 636-642. [PMID: 12759897]
4. Russell, D.W. The enzymes, regulation, and genetics of bile acid synthesis. Annu. Rev. Biochem. 72 (2003) 137-174. [PMID: 12543708]