Asymmetric transformation of enol acetates with esterases from Marchantia polymorpha

Two esterases catalyzing the asymmetric hydrolysis of enol acetates to give optically active α-alkylated ketones were isolated from cultured cells of Marchantia polymorpha by a three-step procedure: hydrophobic chromatography, anion exchange chromatography and gel-filtration chromatography. These esterases had opposite stereoselectivities on protonation of the enol intermediate in the hydrolysis and one of them obviously reversed the stereoselectivity when the chain length and the bulkiness of substituents at the β-position to the acetoxyl group were increased. The internal amino acid sequences of peptide fragments obtained by the proteolysis of the esterases with lysyl endopeptidase had no similarity to those of other hydrolytic enzymes.