ENANTIOSELECTIVITY OF PSEUDOMONAS-CEPACIA AND CANDIDA-RUGOSA LIPASES FOR THE RESOLUTION OF SECONDARY ALCOHOLS - THE EFFECT OF CANDIDA-RUGOSA ISOENZYMES

In this work, the lipase (Pseudomonas cepacia) (PS)- and Candida rugos a lipase (CRL)-catalyzed asymmetric deacylations of the esters of stru cturally different secondary alcohols were studied. Enantioselectivity in the case of lipase PS was always easily predicted according to the sizes of the substituents at the alcoholic stereocenter whereas the f avored enantiomer in the case of CRL strongly depended on the structur e of the racemic alcohol moiety in an ester. In the next step, commerc ial CRL was fractionated into its isoenzymes (A and B). The two isoenz ymes A and B always gave the same enantiopreferences. This observation clearly showed that the heterogeneity of the commercial CRL was not a reason for the reversed enantioselectivity of certain substrates such as cyanohydrin, ol-hydroxycarboxylic acid, and 2,2,2-trihaloethanol d erivatives when compared to the selectivity observed when lipase PS wa s used as a catalyst. (C) 1998 Elsevier Science Inc.