165461-87-0Relevant articles and documents
Modulation of immobilized lipase enantioselectivity via chemical amination
Palomo, Jose M.,Fernandez-Lorente, Gloria,Guisan, Jose M.,Fernandez-Lafuente, Roberto
, p. 1119 - 1127 (2007)
The aspartic and glutamic carboxylic groups of the surface of three different immobilized lipases (those from Candida antarctica (form B) (CAL-B), Thermomyces lanuginose (TLL) and Pseudomonas fluorescens (PFL) have been modified with ethylenediamine (after activation of the carboxylic function with carbodiimide). The exchange of groups with a negative charge for positively charged groups permitted us to greatly alter the activity, specificity and stereoselectivity of the lipase. Thus, in some cases, the activity of the lipases increased after the chemical modification while in other cases the activity was strongly reduced. Moreover, the effect of the experimental conditions on the activity was also strongly altered. Remarkably, the enantioselectivity of the enzymes in the hydrolysis of different mandel ic acid derivatives was strongly modulated. For example, amination of the CNBr-CAL-B preparation greatly increased the enantioselectivity of the enzyme in the hydrolysis of (±)-2-hydroxyphenylacetic acid methyl ester, from an E value of 2 without modification up to E>100, affording (R)-mandelic acid in high purity (ee>99% at 50% conversion) at pH 7 and 4°C. Thus, the chemical modification of lipases seems to be a very powerful tool to improve their performance as enantioselective biocatalvsts.
