Enantioselectivity of a recombinant esterase from Pseudomonas fluorescens

Abstract

A recombinant esterase from Pseudomonas fluorescens (PFE) was produced from E. coli cultures and purified to homogeneity resulting in a specific activity of 120 U/mg ( p-nitrophenylacetate assay). PFE is stable in a wide range of pH (6-9) and active from 30-70 degrees C, but rather unstable at temperatures > 50 degrees C. PFE hydrolyzes a wide range of aliphatic and aromatic esters, but no long chain fatty acid esters. The enzyme showed high rate and enantioselectivity in the resolution of alpha-phenylethanol (E > 100) and its acetate (E = 58), while the closely related alpha-phenylpropanol was converted at very low rate and enantioselectivity. 3-Phenylbutyric acid methylester was hydrolyzed at acceptable rate, but low enantioselectivity (E = 3.4-3.7), whereas 2-phenylbutyric acid ethylester was not a substrate for PFE. (C) 1998 Elsevier Science B.V. All rights reserved.