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Journal ArticleDOI

Strategies in the Preparation of Homochiral Compounds Using Combined Enantioselective Enzymes

01 Jan 1990-Vol. 4, pp 89-104
TL;DR: For irreversible pseudo-first order enzyme kinetics, a relationship was found which describes the dependency of the yield and enantiomeric excess for these systems on the E-values of the separate enzymes and on the ratio of their concentrations.
Abstract: In order to obtain a homochiral product from a racemic substrate, different strategies can be followed using a moderately enantioselective enzymatic catalyst. Two new strategies are presented, involving the simultaneous use of two enzymes, parallel or consecutive. In the parallel system, the substrate enantiomer yielding the unwanted product enantiomer is enantioselectively converted by the second enzyme. In the consecutive system, the substrate enantiomer yielding the desired product enantiomer is itself the preferred product of another enantioselective enzymatic reaction.For irreversible pseudo-first order enzyme kinetics, a relationship was found which describes the dependency of the yield and enantiomeric excess for these systems on the E-values of the separate enzymes and on the ratio of their concentrations. For Michaelis-Menten kinetics, these relationships usually give good approximations.According to these calculations, the yield and enantiomeric excess obtainable with the concepts of combined en...
Citations
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Journal ArticleDOI
TL;DR: The outstanding characteristics of the enantiomeric ratio as a quantitative measure of the effects of physical and chemical conditions on the intrinsic enantioselectivity of enzymes are presented in terms of the difference in Gibbs energies of the diastereomeric enzyme-substrate transition states.

213 citations

Journal ArticleDOI
01 Jan 1993
TL;DR: This review pinpoints the strategies which can be employed to improve the enantio- and diasteroselectivity of hydrolytic enzymes, i.e. esterases, proteases, and lipases.
Abstract: This review pinpoints the strategies which can be employed to improve the enantio- and diasteroselectivity of hydrolytic enzymes, i.e. esterases, proteases, and lipases. The influence of variations of reactants, — enzyme and substrate — and conditions — kinetics, medium, temperature, pH — on the chiral recognition process of the enzyme is discussed with examples from the recent literature.

66 citations

Journal ArticleDOI
01 Jan 1992
TL;DR: This paper systematically treats the deviations from the model of Chen that may occur for bi-bi reactions obeying ping-pong or ternary complex kinetics for reactions with multiple substrates or products.
Abstract: The course of the kinetic resolution of a racemic compound by an enantioselective enzyme can often be described using Michaelis-Menten kinetics. This description (Chen et at., 1982, 1987) is formally not correct for reactions with multiple substrates or products. Van Tol et at. (1992) showed for the lipase-catalyzed resolution of glycidyl butanoate that the ping-pong kinetic mechanism has to be taken into account. This paper systematically treats the deviations from the model of Chen that may occur for bi-bi reactions obeying ping-pong or ternary complex kinetics. The course of the enantiomeric excess as a function of the degree of conversion was found to be dependent on two or three kinetic parameters (in contrast to the single E-value of Chen), on the thermodynamic equilibrium constant and on the ratio of initial concentrations of the reactants. This ratio can be used to some extent to manipulate the enantiomeric excess in a resolution process.

45 citations

References
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Book
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1,052 citations

Journal ArticleDOI

581 citations

Journal ArticleDOI
TL;DR: In this paper, the broad applicability of horse liver alcohol dehydrogenase-catalyzed oxidations of meso-diols as a route to chiral lactones of asymmetric synthetic value is described.

259 citations