MOLECULAR MODELING STUDIES OF SUBSTRATE-BINDING TO THE LIPASE FROM RHIZOMUCOR-MIEHEI

Lipase enzymes have found increasingly widespread use, especially in b iotransformation reactions in organic synthesis. Due to their efficien cy and high enantioselectivity. they call be employed in a variety of reactions to carry out asymmetric hydrolyses, esterifications and tran sesterification. However, tile reasons for their stereospecificity hav e not been fully correlated with the enzyme structure. Employing molec ular modelling techniques and existing experimental data, a transecter ification reaction using Rhizomucor miehei lipase was studied. The res ults indicate that the major controlling factor for this reaction is h ydrophobic in nature providing support for previous literature hypothe sis. In addition, computational experiments suggest that the origin of enantioselectivity is the formation of essential hydrogen bonds in an d around the catalytic triad of active site residues. Only one enantio mer of the substrate is able to form these hydrogen bonds during the f ormation of the first tetrahedral transition state.