Enzyme-catalyzed synthesis

Scheme 5.10 Enzyme-catalyzed synthesis of a-amino acids from hydantoins.

Since the beginning of the 20th century, organic solvents have been used in enzymatic reaction media [30]. Biocatalytic reactions in water-organic biphasic media were first carried out by Cremonesi et al. [31] and by Buckland et al. [32] less than 30 years ago. Their work aimed at the conversion of high concentrations of poorly water soluble components, particularly steroids. Later, biphasic systems were used for enzyme-catalyzed synthesis reactions that were unfavored in water, changing the reaction equilibrium towards the higher yield of the product, such as esters or peptides. 

Effenberger, F., Hoersch, B., Weingart, F. et al. (1991) Enzyme-catalyzed synthesis or (/ )-ketone-cyanohydrins and their hydrolysis to (R)-a-hydroxy-a-methyl-carboxylic acids. Tetrahedron Letters, 32, 2605-2608. 

Pseudomonine (Fig. 27, 76) is produced by Pseudomonas fluorescens strains (7, 228) and by P. entomophila, where it can act as a secondary siderophore (209). The substituents on C-4 and C-5 of the isoxazolinone ring are in trans positions (333). The complex formation has not been studied. In vitro enzyme-catalyzed synthesis studies (333,388) showed that initially the intermediate pre-pseudomonine (Fig. 24, 79) is formed, which non-enzymatically rearranges to pseudomonine. 

Finally in this sechon, a novel approach has been developed for the enzyme-catalyzed synthesis of D-tert-leucine 55 from the corresponding racemate (Scheme... 

Biochemical Retrosynthesis of 2 -Deoxyribonucleosides from Glucose Acetaldehyde and a Nucleobase Three-Step Multi-Enzyme-Catalyzed Synthesis... 

Kobayashi, S., Kaplan, D., and Ritter, H. 2006. Enzyme-Catalyzed Synthesis of Polymers. Springer, New York. 

Knani D, Gutman AL, Kohn DH (1993) Enzymatic polyesterification in organic media. Enzyme-catalyzed synthesis of linear polyesters. I. Condensation polymerization of linear hydroxyester. II. Ring-opening polymerization of e-caprolactone. J Polym Sci A Polym Chem 31 1221-1232... 

Varma IK, Albertsson A-C, Rajkhowa R, Srivistava RK (2005) Enzyme catalyzed synthesis of polyesters. Prog Polym Sci 30 949-981... 

B. The pyruvate dehydrogenase (PDH) complex, which consists of multiple copies of three separate enzymes, catalyzes synthesis of acetyl CoA from pyruvate (Figure 7-1). 

Toone, E., Simon, E., Bednarski, M. and Whitesides, G. (1989) Enzyme-catalyzed synthesis of carbohydrates. Tetrahedron, 45, 5365-5422. 

C.-H. Wong, S. L. Haynie, and G. M. Whitesides, Enzyme catalyzed synthesis of IV-acetyl-lactosamine with in situ regeneration of uridine 5 diphosphate glucose and uridine 5 -diphos-phate galactose, J. Org. Chem. 47 5416 (1982). 

Y. Ichikawa, G.-I. Shen, and C.-H. Wong, Enzyme-catalyzed synthesis of sialyl oligosaccharide with in situ regeneration of CMP-sialic acid, J. Am. Chem. Soc. 113 4698 (1991). 

Wong C-H, Drueckhammer DG, Durrwachter JR, Lacher B, Chauvet CJ, Wang YF, Sweers HM, Smith GL, Yang LJS, Hennen WJ (1989) Enzyme-catalyzed synthesis of carbohydrates. In Horton D, Hawkins LD, McGarvcy GJ (eds) Trends in Synthetic Carbohydrate Chemistry. American Chemical Society, Washington, vol. 386, p 317... 

L. G. Lee and G. M. Whitesides, Preparation of optically active 1,2-diols and a-hydroxy ketones using glycerol dehydrogenase as catalyst limits to enzyme-catalyzed synthesis due to noncompetitive and mixed inhibition by product, J. Org. Chem. 1986, 51, 25-36. 

F. Effenberger, B. Hoersch, S. Foerster, andT. Ziegler, Enzyme-catalyzed reactions. 5. Enzyme-catalyzed synthesis of (S)-cyanohydrins and subsequent hydrolysis to (S)-a-hydroxy-carboxylic adds, Tetrahedron Lett. 1990, 31, 1249-1252. 

Every zirconium atom forms an active complex, as shown by Tait (103) and Chien and Wang (104), producing about 46,000 polymer chains per hour. (This efficient use of the zirconium atoms is contrasted to Ziegler-Natta and Phillips polymerization, in which only a small fraction of the metal centers are active.) The insertion time of one ethylene unit is only 3 x 1(T5 s. The rates are comparable to those observed for some enzymes catalyzing synthesis reactions. The analogy to enzymes is manifested in others ways as well—for example, the influence of substitution, regioselectivity, and stereospecificity. 

Guan H. P., Kuriki, T., Sivak, M., and Preiss, J. 1995. Maize branching enzyme catalyzes synthesis of glycogen-like polysaccharide in glgB-deficient Escherichia coli. Proc. Natl. Acad. Science USA 92, 964-967. 

A completely different enzyme-catalyzed synthesis of cyanohydrins is the lipase-catalyzed dynamic kinetic resolution (see also Chapter 6). The normally undesired, racemic base-catalyzed cyanohydrin formation is used to establish a dynamic equilibrium. This is combined with an irreversible enantioselective kinetic resolution via acylation. For the acylation, lipases are the catalysts of choice. The overall combination of a dynamic carbon-carbon bond forming equilibrium and a kinetic resolution in one pot gives the desired cyanohydrins protected as esters with 100% yield [19-22]. 

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