Optimum conformational flexibility of subtilisin to maximize the enantioselectivity for subtilisin-catalysed transesterification in an organic solvent with an addition of dimethyl sulfoxide
Metal ions dramatically enhance the enantioselectivity for lipase-catalysed reactions in organic solvents
作者:Takashi Okamoto、Ebara Yasuhito、Shin-ichi Ueji
DOI:10.1039/b514885e
日期:——
simple and a powerful method to enhance the enantioselectivity for lipase-catalysed transformations in organicsolvents by an addition of metal ion-containing water to the reaction mixture. In this paper, various metal ions such as LiCl or MgCl2 are tested to improve the enantioselectivity for the model reactions. The enantioselectivities obtained are dramaticallyenhanced, the E values of which are about
Dimethyl sulfoxide as a co-solvent dramatically enhances the enantioselectivity in lipase-catalysed resolutions of 2-phenoxypropionic acyl derivatives
作者:Keiichi Watanabe、Shin-ichi Ueji
DOI:10.1039/b100182p
日期:——
the enantioselectivity for subtilisin-catalysed hydrolysis of ethyl 2-(4-substituted phenoxy)propionates in aqueous buffer is found to be dramatically enhanced by addition of dimethyl sulfoxide (DMSO). In our present work, as one of the useful methods for improving the enzyme’s enantioselectivity, this approach using DMSO is tested for both hydrolysis and transesterification catalysed by various lipases
The addition of sodium dodecyl sulfate (SDS) resulted in a dramatic improvement of the enantioselectivity of the lipasecatalyzed hydrolysis of racemic butyl 2-(4-substituted phenoxy)propanoates, racemic butyl 2-(4-isobutylphenyl)propanoate, and racemic butyl 2-(6-methoxy-2-naphthyl)propanoate in an aqueous buffer solution. An increase in the E value by up to two orders of magnitude was observed for some esters. As to the effects of SDS on the structure of a lipase, FT-IR and fluorescence measurements suggest some conformational change and/or an increase of the flexibility of the lipase, although the native secondary structure of the lipase is held even in the presence of 100 mM SDS. The origin of the enantioselectivity enhancement brought about by the addition of SDS is briefly discussed on the basis of the values of the initial rates obtained for each enantiomer of the substrate. (c) 2005 Elsevier Ltd. All rights reserved.