Epoxide hydrolases overexpression

As a result of the flux analysis, the most promising target for pathway modification to augment the yield of desired trans- (lK,2K)-indanediol is enhanced selective hydrolysis of indane oxide to trans-(lR,2J )-indanediol, either by modification of the culture conditions or by overexpression of an epoxide hydrolase. 

In spite of these very interesting results, the use of mammalian epoxide hydrolases is still severely hampered - or even impossible - for large-scale industrial production. Even overexpressed enzymes are not currently available in large enough quantities at a reasonable price. 

Several membrane-bound and soluble epoxide hydrolases from mammalian origin have been purified and (at least partially) sequenced. Some of them have also been cloned and overexpressed, which is the case for the soluble EH from rat liver which has been overexpressed in Escherichia cob 54, 55. This enzyme (as well as its microsomal analog) was shown to share an amino acid sequence similarity to a region around the active center of a bacterial haloalkane dehalogenase 56, an enzyme with known three-dimensional structure that belongs to the a/(3-hydrolase fold-family 571. Rat soluble EH forms a dimer from two complete structural monomeric units, both possessing a distinct active site. The EH activity is known to be located close to the C-terminal unit, while the function of the N-terminal unit remains unknown 581. 

Deng Y, Edin ML, Theken KN, Schuck RN, Flake GR Kannon MA, DeGraff LM, Lih FB, Foley J, Bradbury JA, Graves JR Tomer KB, Falck JR, Zeldin DC, Lee CR (2011) Endothelial CYP epoxygen-ase overexpression and soluble epoxide hydrolase disruption attenuate acute vascular inflammatory responses in mice. FASEB J 25 703-713... 

Regardless of the biological source, all epoxide hydrolases found to date do not possess a metal atom or a prosthetic group, and do not require any cofactors. Since the overexpression of a mammalian epoxide hydrolase did not lead to a highly active enzyme... 

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