Molecular recognition of an acyl-enzyme intermediate on the lipase B from Candida antarctica

Abstract

This investigation provides evidences of the acyl enzyme species involved in theinteraction of R/S-ketoprofen with the lipase B from Candida antarctica. The interaction between the profen and the enzyme was studied by in situ Time-Resolved ATR-FTIR both in static and transient conditions. Particularly, modulation excitation spectroscopy (MES) with phase sensitive detection (PSD) allowed to univocally distinguishing the signals belonging to the interaction between ketoprofen and the enzyme from the strong background signals. These experimental tools coupled with theoretical DFT analysis allowed to propose various species due to the interaction of ketoprofen with serine through H bonding (without reaction) and the acyl enzyme species (ester bond formation) that are the intermediates in the biocatalytic assisted esterification andhydrolysis using lipases.