Structural and energetic determinants for enantiopreferences in kinetic resolution of lipases

Lipases can catalyze the hydrolysis, transesterification and amidation of a broad range of esters and amides with distinct stereopreference in addition to their physiological function of cleaving triacylglycerols (Schmid and Verger, 1998). As a consequence of their stability and large‐scale availability, they have found widespread applications in the enantioselective synthesis of precursors to pharmaceuticals and in the kinetic resolution of racemic mixtures (Reetz, 2002). From a thermodynamic point of view, the latter ability to accomplish chiral discrimination results from a difference in Gibbs free energy of activation, ΔRSΔG‡ (Eyring and Polanyi, 1931; Phillips, 1992, 1996). It is experienced by both stereoisomeric transition states formed with the two enantiomers in the rate‐limiting step with respect to the ground state. In order to predict and subsequently design enantioselectivity (Kazlauskas, 2000) towards different substrates, it is necessary to understand the structural and energetic determinants by which lipases distinguish enantiomers at a molecular level.