Journal of Colloid and Interface Science, Vol.170, No.2, 351-357, 1995
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 hydrolysis of ester bonds in, for example, triacylglycerol molecules. An important characteristic of this enzyme is that it is water-soluble whereas its substrate is water-insoluble. The adsorption of Lipolase was studied on several polystyrene latices and glass in order to determine the effect of the nature of the solid phase and to determine the interactions which are of importance for the adsorption. Electrostatic interaction and dehydration of hydrophobic surfaces are the main driving forces for Lipolase adsorption. Under attractive electrostatic conditions between the surface and the enzyme, the plateau value of the isotherm corresponds to saturated monolayer coverage. Under conditions where 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 protein Savinase. However, Lipolase adsorbs much less on hydrophobic interfaces under electrostatic repulsive conditions than proteins examined in the literature, indicating that the dehydrated contact area between enzyme and surface is relatively small and that consequently the enzyme does not unfold significantly upon adsorption.