Monolayer technique for the study of the hydrolysis of dilaurin isomers biocatalysed by different lipases

To investigate interfacial activation phenomenon on lipolytic enzymes we carried out kinetic studies employing the monolayer technique. The use of a substrate in monofilm state allows the monitoring, during the biocatalysed reactions, of several physico-chemical parameters and permits the modification of the "quality of interface". The substrates used in this study were diglycerides; in particular dilaurin isomers were hydrolysed employing different microbial lipases from different sources as catalysts. In fact 1,2-sn-dilaurin and 2,3-sn-dilaurin are optically active antipodes, while 1,3-sn-dilaurin is a prochiral compound. The influence of surface pressure and the consequent substrate orientation on the hydrolysis rate, stereoselectivity and regioselectivity were studied, carrying out hydrolysis reactions at different compression degree. Data show that the enzyme surface interaction affects enzyme activity and specificity.