Esterase, thermophilic

Chirazymes. These are commercially available enzymes e.g. lipases, esterases, that can be used for the preparation of a variety of optically active carboxylic acids, alcohols and amines. They can cause regio and stereospecific hydrolysis and do not require cofactors. Some can be used also for esterification or transesterification in neat organic solvents. The proteases, amidases and oxidases are obtained from bacteria or fungi, whereas esterases are from pig liver and thermophilic bacteria. For preparative work the enzymes are covalently bound to a carrier and do not therefore contaminate the reaction products. Chirazymes are available form Roche Molecular Biochemicals and are used without further purification. 

Rhee J-K, D-G Ahn, Y-G Kim, J-W Oh (2005) New thermophilic and thermostable esterase with sequence similarity to the hormone-sensitive lipase family cloned from a metagenomic library. Appl Environ Microbiol 71 817-825. 

Mueller RF, Nielsen PH (1996) Characterization of thermophilic consortia from tTwo souring oil reservoirs. Appl Environ Mcrobiol 62 3083-3087 Niazi JH, Prasad DT, Karegoudar TB (2001) Initial degradation of dimethylphtha-late by esterases from Bacillus species. FEMS Microbiol Lett 196 201-205 Obst M, Krug A, Luftmann H, Steinbuchel A (2005) Degradation of cyanophycin by Sedimentibacter hongkongensis strain KI and Citrobacter amalonaticus... 

The high thermostability of natural thermophilic enzymes is usually accompanied by increased resistance to other forms of denaturation, such as cleavage by proteases and chemical denaturation by guanidine hydrochloride or urea. A similar trend is seen in the evolved thermostable esterases. Thermostable 8G8 is more resistant than wild type to cleavage by trypsin and to denaturation by guanidine hydrochloride (Gershenson et al, 2000). 

The most thermophilic variant of j/NB esterase, 8G8, has only thirteen mutations compared to the wild-type esterase, making it 97% identical to the wild-type esterase sequence, with a root-mean-square deviation of only 0.44 A between the two C backbone structures. As with the 5-6C8 organophile structure, the catalytic triads of 8G8 and wild-type / NB esterase are superimposable. This high sequence and structural identity, in conjunction with the availability of crystal structures for both the wild type and thermophile, affords an interesting opportunity to study the structural basis for thermostability. Thermophile 8G8 is the product of eight generations of directed evolution, screening for retention of activity... 

Other thermophilic enzymes from archaea may be used for analytical and preparative purposes. For instance, the glucose dehydrogenase from S. solfataricus [70] may serve as a suitable tool for glucose determination, whereas the relatively broad substrate spectrum of the esterase from S. acidocaldarius (catalyzes the acyl transfer to various alcohols and amines [71]) or of the alcohol dehydrogenase from S. solfataricus (oxidizes various aliphatic and aromatic alcohols [72]) makes these enzymes rather attractive for... 

D. Lang, M. Rossi, and C. Pedone, A snapshot of a transition state analogue of a novel thermophilic esterase belonging to the subfamily of mammalian hormone-sensitive lipase, J. Mol. Biol., 2000, 303, 761-771. 

We end this chapter with two much simpler reactions - a couple of desymmetrisations - each special in their own way. The hrst is amazingly efficient, using a lipase/esterase from a thermophilic organism supplied as a recombinant protein by the Diversa corporation. The symmetrical Diels-Alder adduct 231 is rapidly and perfectly desymmetrised to the monoacid61 232 at 70 °C. 

Femmidez-Lafuente R, Cowan D, Wood A (1995) Hyperstabilization of a thermophilic esterase by multipoint covalent attachment. Enzyme Microb Technol 17 366-372 Femmidez-Lafuente R, Armisen P, Sabuquillo P et al. (1998) Immobilization of lipases by selective adsorption on hydrophobic supports. Chem Phys Lipids 93 185-197 Femmidez-Lafuente R, Rodriguez V, Mateo C et aL (1999) Stabilization of enzymes (D-amino acid oxidase) against hydrogen peroxide via immobilization and post-immobihzation techniques. J Mol Catal B Enzym 7 173-179... 

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