Biocatalysis dehydrogenase

In order to broaden the field of biocatalysis in ionic liquids, other enzyme classes have also been screened. Of special interest are oxidoreductases for the enan-tioselective reduction of prochiral ketones [40]. Formate dehydrogenase from Candida boidinii was found to be stable and active in mixtures of [MMIM][MeS04] with buffer (Entry 12) [41]. So far, however, we have not been able to find an alcohol dehydrogenase that is active in the presence of ionic liquids in order to make use of another advantage of ionic liquids that they increase the solubility of hydrophobic compounds in aqueous systems. On addition of 40 % v/v of [MMIM][MeS04] to water, for example, the solubility of acetophenone is increased from 20 mmol to 200 mmol L ... 

M. R. Kula, U. Kragl, Dehydrogenases in the synthesis of chiral compounds" in R. Patel, Stereoselective Biocatalysis, Marcel Dekker, 2000, 839. 

Weckbecker, A. and Hummel, W. (2006) Cloning, expression, and characterization of an (/ (-specific alcohol dehydrogenase from Lactobacillus kefir. Biocatalysis and Biotransformation, 24 (5), 380-389. 

Biocatalysis is still an emerging field hence, some transformations are more established than others.Panke et alP have performed a survey of patent applications in the area of biocatalysis granted between the years 2000 and 2004. They found that although hydrolases, which perform hydrolyses and esterifications, still command widespread attention and remain the most utilized class of enzyme (Figure 1.5), significant focus has turned towards the use of biocatalysts with different activities and in particular alcohol dehydrogenases (ADHs) - also known as ketoreductases (KREDs) - used for asymmetric ketone reduction. 

The first sub-class of the oxido reductases is 1.1, and it comprises the dehydrogenases which act on primary or secondary alcohols or hemiacetals. They are mostly used for reduction of ketones and aldehydes. Two other categories are oxygenases and oxidases. The latter is not much used in biocatalysis. 

Dehydrogenases are very valuable en2ymes in biocatalysis, although one of their challenges is the use of an additional cofactor, such as NAD(P)(H). There are several advantages to dealing only with dehydrogenases that are dependent on NAD(H) but not on NADP(H) ... 

Ohshima, T., Soda, K. Stereoselective Biocatalysis Amino Acid Dehydrogenases and Their Applications. In Stereoselective Biocatalysis, Patel, R. N. Ed., Marcel Dekker, Inc. New York, 2000, p. 877. 

Enzyme (and nucleic acid) immobilization This application of NPs is the one that is discussed in the present chapter. Various types of enzymes can be immobilized onto NPs [176]. Functionalization of NPs with co-factors (as NAD+) facilitates the biocatalysis from enzymes that need the presence of a cofactor (as lactate dehydrogenase or glucose oxidase) [188]. 

Tramper 1 (1994) Applied biocatalysis from product request to idea to product. In Cabral IMS, Boros DBL, Tramper 1 (eds). Apphed biocatalysis. Harwood Acad Publ, Chur, pp 1 5 Trivedi AH, Spiess AC, Daussmann T et al. (2006) Effect of additives on gas-phase catalysis with immobilised Thermoanaerobacter species alcohol dehydrogenase. Appl Microbiol Biotechnol... 

Zaitseva, E.A. et ah, Stabilization mechanism of glucose-6-phosphate dehydrogenase. Biocatalysis, 41, 127, 2000. 

Multistep biocatalysis for the preparation of optically pure epoxides was applied by Sello and coworkers [24, 25]. The commercially available 3-vinyl benzaldehyde was the substrate of choice for the synthesis of 3-(oxiran-2-yl) benzoic acid in high yields and optical purity by solely employing enzyme catalysis (Scheme 3.6). This goal was achieved by applying a mixed culture approach with different recombinant E. coli strains expressing, individually, both oxidizing biocatalysts. One strain contained a native ADH and a SMO from Pseudomonas Jiuorescens ST, while a second one expressed a naphthalene dihydrodiol dehydrogenase (NDDH) from P. Jiuorescens N3. 

Toda, FI., Imae, R., and Itoh, N. (2012) Efficient biocatalysis for the production of enantiopure (S)-epoxides using a styrene monooxygenase (SMO) and Leif-sonia alcohol dehydrogenase (LSADH) system. Tetrahedron Asymmetry, 23, 1542-1549. 

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