Esterases, chiral recognition

In the case of lipases and esterases, chiral recognitions are not so strict. Both enantiomers were incorporated to the enzyme to form the substrate-enzyme complex. However, the slow reacting enantiomer lacked the necessary hydrogen-bonding interaction, for example in the hydrolysis of menthol acetate, between the substrate menthol and the enzyme histidine group for the reaction to proceed further (Figure 3(b)).2 3 The explanation was also supported by the observation in the esterification reaction of 1-phenylethanol by lipases.4 Km values of the slow and fast reacting... 

As shown in Scheme 2.27, the prochiral center may be moved from the site of the reaction into the (3-position. Thus, chiral recognition by PLE [214-218] and a-chymotrypsin [219-222] is retained during the desymmetrization of prochiral 3-substituted glutaric diesters. Whole cells of Acinetobacter lowfii and Arthrobac-ter spp. have also been used as a source for esterase activity [223] and, once again, depending on the substitutional pattern on carbon-3, the desymmetrization can lead to both enantiomeric products. 

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