Kinetic modeling of lipase-catalysed hydrolysis of triacylglycerol in a reverse micelle system for the determination of integral stereoselectivity

A kinetic model describing the integral stereoselectivity of lipase, which refers to selectivities for all positions of triacylglycerol, diacylglycerol, and monoacylglycerol isomers, was developed. Based on the Ping-Pong Bi-Bi mechanism, the model incorporates a stepwise hydrolysis reaction from triacylglycerol to glycerol with non-enzymatic acyl migration of diacylglycerol and monoacylglycerol isomers. With the kinetic model, lipase-catalysed hydrolysis of trioleoylglycerol (TOG) was investigated using lipases from the porcine pancreas, Chromobacterium viscosum, and Pseudomonas fluorescens in a reverse micelle system. By varying the initial substrate concentration, the model was able to provide a good description of stepwise TOG hydrolysis by each lipase, with the lipases exhibiting different selectivity. With the kinetic constants derived from the model, the stereoselective nature of lipases can be estimated comprehensively and quantitatively while considering the entire process of lipase-catalysed TOG hydrolysis. Therefore, the proposed approach will provide valuable information for the effective selection, screening, and development of lipases, particularly the production of lipids with regioisomerically or enantiomerically specific structures.N