The Effect of Temperature on the Enantioselectivity of Lipase-Catalyzed Reactions; Case Study: Isopropylidene Glycerol Reaction

Abstract

Commercial lipase (triacylglycerol lipase (EC 3.1.1.3) of Burkholderia cepacia (40 U/mg) in its crude form has been used in the kinetic resolution of enzyme-catalyzed reaction of 1,2-O-isopropylidene-sn-glycerol and vinyl acetate as acyl donor in the organic solvent n-hexane. It was observed that the enantioselectivity is in the range of 2.295 to 2.235 while ΔΔGD,L -73.408 to -75.682 kJ/mol at 35 °C and 55 °C, respectively . This shows that any increase in the reaction temperature led to an increased final conversion, but it has no effect on the enantioselectivity of the reaction. Also, the thermodynamic effect of temperature on the Gibbs free energy in the lipase-catalyzed kinetic resolution of the reaction between racemic isopropylidene glycerol and vinyl acetate remains in the small range. By using this type of analysis, the researchers may predict if they should increase or decrease the temperature to enhance the selectivity of enzyme in catalyzing a reaction.