DRIVING FORCES FOR ENZYME ADSORPTION AT SOLID-LIQUID INTERFACES .2. THE FUNGAL LIPASE LIPOLASE

Lipolase is the trade name for a fungal lipase that can catalyze the h ydrolysis of ester bonds in, for example, triacylglycerol molecules. A n important characteristic of this enzyme is that it is water-soluble whereas its substrate is water-insoluble. The adsorption of Lipolase w as studied on several polystyrene latices and glass in order to determ ine the effect of the nature of the solid phase and to determine the i nteractions which are of importance for the adsorption. Electrostatic interaction and dehydration of hydrophobic surfaces are the main drivi ng forces for Lipolase adsorption. Under attractive electrostatic cond itions between the surface and the enzyme, the plateau value of the is otherm corresponds to saturated monolayer coverage. Under conditions w here dehydration of the hydrophobic surface is almost compensated for by electrostatic repulsion the lateral repulsion between the adsorbed enzymes becomes also important and contributes to the surface coverage . The adsorption mechanism of Lipolase is similar to that of the prote in Savinase. However, Lipolase adsorbs much less on hydrophobic interf aces under electrostatic repulsive conditions than proteins examined i n the literature, indicating that the dehydrated contact area between enzyme and surface is relatively small and that consequently the enzym e does not unfold significantly upon adsorption. (C) 1995 Academic Pre ss, Inc.