INTERFACIAL ACTIVATION OF LIPASES - FACTS AND ARTIFACTS

An important aspect of lipolytic enzymes is the unique physicochemical character of the reactions they catalyse at lipid-water interfaces, i nvolving interfacial adsorption and subsequent catalysis sensu stricto , Lipases are now used as catalysts in aqueous as well as low-water me dia and accept various molecules as substrates, They were previously d efined in kinetic terms, based on 'interfacial activation', This pheno menon was not found among esterases, Recently determined 3D structures of some, but not all, lipases show a 'lid' controlling access to the active site, Thus, the presence of a lid, and 'interfacial activation' , are unsuitable criteria for classifying specific esterases, Conseque ntly, lipases can be pragmatically redefined as carboxyl-esterases act ing on long-chain acylglycerols: they are simply fat-splitting 'fermen ts'.