Epoxide hydrolases styrene oxide

Furstoss et al. have reported their studies on the use of an epoxide hydrolase with four styrene oxide derivatives (Figure 5.26) [39]. The (R)-diol (43) was obtained in 91% ee at 100% conversion from racemic (42), demonstrating an enantioconvergent... 

The data in Table 10.1 suggest that the reactivity of epoxide hydrolase toward alkene oxides is highly variable and appears to depend, among other things, on the size of the substrate (compare epoxybutane to epoxyoctane), steric features (compare epoxyoctane to cycloalkene oxides), and electronic factors (see the chlorinated epoxides). In fact, comprehensive structure-metabolism relationships have not been reported for substrates of EH, in contrast to some narrow relationships that are valid for closely related series of substrates. A group of arene oxides, along with two alkene oxides to be discussed below (epoxyoctane and styrene oxide), are compared as substrates of human liver EH in Table 10.2 [119]. Clearly, the two alkene oxides are among the better substrates for the human enzyme, as they are for the rat enzyme (Table 10.1). 

Generally monosubstituted and dx-l,2-disubstituted epoxides are good substrates for EH while tri-, tetra or tra s-l,2-disubstituted ones are poor or non-substrates. Resolutions of epoxides using microsomal epoxide hydrolases, mEHs show that cis-2-alkyl substituted styrene oxides gave very high E-values when R=Me or Et (Figure 2.18a). A series of cis-... 

Water conjugation Water Epoxide hydrolase (microsomes) Arene oxides, cis-disubstituted and mono-substituted oxiranes Benzopyrene 7,8-epoxide, styrene 1,2-oxide, carbamazepine epoxide... 

Hydration of epoxides catalyzed by epoxide hydrolase is involved in both detoxication and intoxication reactions. With high concentrations of styrene oxide as a substrate, the relative activity of hepatic microsomal epoxide hydrolase in several animal species is rhesus monkey > human = guinea pig > rabbit > rat > mouse. With some substrates, such as epoxidized lipids, the cytosolic hydrolase may be much more important than the microsomal enzyme. 

Epoxide is an important intermediate for various bioactive compounds, so the demand for the chiral epoxide is increasing. Epoxide hydrolase can hydrolyze epoxide enantioselectively (Figure 20).21 For example, Aspergillus niger was used for the hydrolysis of carvone epoxide (Figure 20(a)).2 11 In the reaction of styrene oxide, the... 

Dehydrogenation A-Demethylation Hydroxylation Epoxidation Sulfoxidation Oxidations Acetaminophen, benzidine, DES, epinephrine Dimethylaniline, benzphetamine, aminocarb Benzo[a]pyrene, 2-aminofluorene, phenylbutazone 7,8-Dihydrobenzo[a]pyrene Methylphenylsulfide FANFT, ANFT, bilirubin Esterases and Amidases Paraoxon, dimethoate, phenyl acetate Epoxide Hydrolase Benzo(a)pyrene epoxide, styrene oxide DDT-Dehydrochlorinase p,p- DDT Glutathione Reductase Disulfiram... 

The existence of a cytosolic epoxide hydrolase was first indicated by its ability to hydrolyze analogs of insect juvenile hormone not readily hydrolyzed by microsomal epoxide hydrolase. Subsequent studies demonstrated a unique cytosolic enzyme catalytically and structurally distinct from the microsomal enzyme. It appears probable that the cytosolic enzyme is peroxisomal in origin. Both enzymes are broadly nonspecific and have many substrates in common. It is clear, however, that many substrates hydrolyzed well by cytosolic epoxide hydrolase are hydrolyzed poorly by microsomal epoxide hydrolase and vice versa. For example, l-(4 -ethylphenoxy)-3,7-dimethy I -6,7-epoxy-//7//i,v-2-octene, a substituted geranyl epoxide insect juvenile hormone mimic, is hydrolyzed 10 times more rapidly by the cytosolic enzyme than by the microsomal one. In any series, such as the substituted styrene oxides, the trans configuration is hydrolyzed more rapidly by the cytosolic epoxide hydrolase than is the cis isomer. At the same time, it should remembered that in this and other series,... 

CIS-H4 and trans-P-mcthyl styrene 85 oxides have been tritium labelled also and used for biochemical characterization of the various forms of epoxide hydrolase. 

Herrero ME, Arand M, Hengstler JG, Oesch F. 1997. Recombinant expression of human microsomal epoxide hydrolase protects V79 Chinese hamster cells from styrene oxide—but not from ethylene oxide—induced DNA strand breaks. Environ. Mol. Mutagen. 30 429-39... 

Fig. 20. Resolution of styrene oxide by A. niger and B. sulfurescens epoxide hydrolases. Deracemization of styrene oxide by using a mixture of these two fungi [175]...

Fig. 23. Fungal epoxide hydrolase. Preparative scale resolution of para-bromo styrene oxide using a two-liquid-phase process [213]...

Interestingly, the bacterial epoxide hydrolase from Agrobacterium radiobacter ADI seems to hydrolyze para-substituted styrene oxides with opposite enantiopreference when compared to EHs from fungi or yeast[n8]. Although initial selectivities were... 

For the first time, two novel epoxide hydrolases were discovered in Vigna radiata (mung bean) in our laboratory, either of which can catalyze enantio-convergent hydrolysis of styrene epoxides (Scheme 2.3). Their regioselectiv-ity coefficients are more than 90% for/ nitrostyrene oxide. Furthermore, the... 

Recently, the characterization of NcsF2, one of two epoxide hydrolases encoded by the NCS gene cluster, which catalyzed regiospecific addition of H2O to C-2 of both R)- and (5)-styrene oxides to afford (/ )- and (5)-1-phenyl-1,2-ethanediols, respectively, was reported, supporting its proposed role in 301 biosynthesis [329]. 

DESs have also proven to be suitable as cosolvent for enzymatic reactions in aqueous solution. Gorke et al. [8] have reported that upon addition of 10% of the ChCl/glycerol DES, the hydrolysis of p-nitrophenyl acetate was accelerated moderately when catalyzed by several esterases a threefold increase for pig liver esterase (PLE) and Rhizopus oryzae esterase (ROE) and a 25% increase for Pseudomonas fluorescens esterase (PFE) and CALB. The presence of the same DES in aqueous solution also triggered an up to 20-fold enhancement in the rate of the epoxide hydrolase (from Agrobacterium radiobacter)-cslaiyzed hydrolysis of styrene oxide. In fact, there was a bell-shaped relationship between the reaction rate and the DES content, as shown in Figure 25.5. 

Figure 25 Conversion obtained in the hydrolysis of styrene oxide catalyzed by epoxide hydrolase ADI from Agrobacterium radiobacter as a function of the volume fraction of the ChCl/glycerol DES in aqueous solution. This figure is drawn by using the data taken from Gorke et al. [8],...

J.-H. Woo, E.Y. j e, Enantioselective hydrolysis of racemic styrene oxide and its substituted derivatives using newly-isolated Sphingopyxis sp. exhibiting a novel epoxide hydrolase activity, Biotechnol. Lett. 36 (2014) 357-362. 

W-J Ghen, W-Y Lou, M-H Zong, Asymmetric hydrolysis of racemic styrene oxide to (R)-l-phe-nyl-l,2-ethanediol catalyzed by Mung bean epoxide hydrolase. Am. Chem. Soc., pp. ORGN-667, 2011. 

Monteide, M.I., Lombard, M., Archelas, A., Cronin, A., Arand, M. and Furstoss, R. (2004) Enzymatic transformations. Part 58 Enantioconvergent biohydrolysis of styrene oxide derivatives catalysed by the Solanum tuberosum epoxide hydrolase. Tetrahedron Asymmetry, 15,2801-2805. 

Yildirim, D., Tiikel, S.S., Alptekin, O. and Alagoz, D. (2013) Immobilized Aspergillus niger epoxide hydrolases cost-effective biocatalysts for the preparation of enantiopure styrene oxide, propylene oxide and epichlorohydrin. /. Mol. Catal. B Enzym., 88, 84r-90. 

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