Authors: Jessica Rehdorf Geoffrey A Behrens GiangSon Nguyen Robert Kourist Uwe T Bornscheuer
Publish Date: 2011/07/16
Volume: 93, Issue: 3, Pages: 1119-1126
Abstract
An esterase from Pseudomonas putida JD1 PPE was successfully cloned actively expressed in Escherichia coli and characterized It was discovered that PPE is more active towards shortchain esters hydrolyzed δvalerolactone and εcaprolactone and was most active at 37°C and pH 8 After purification to homogeneity by Ni–NTAassisted affinity chromatography the kinetic parameters K M and k cat were determined for pnitrophenyl acetate and butyrate respectively showing better catalytic efficiency for hydrolysis of the acetate residue Investigation of the protein sequence revealed not only the classical catalytic triad for carboxylesterases additionally the interesting GGGAXmotif which is associated to activity towards tertiary alcohols was found Indeed enzymatic activity was shown for a set of different tertiary alcohols with enantioselectivities up to E = 20 suggesting PPE to be a promising biocatalyst In addition PPE also hydrolyzed 4hydroxyphenyl acetate the product of a Baeyer–Villiger monooxygenasecatalyzed oxidation of 4hydroxyacetophenone with a specific activity of 3436 U/mg suggesting a physiological role in P putida JD1
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