Hydrolysis characterization of phospholipid monolayers catalyzed by different phospholipases at the air–water interface

Combination of some newly developed microscopic and spectroscopic techniques with conventional Langmuir monolayer method can provide more quantitative information with the molecular orientation and reorganization process of spread amphiphilic molecules at the air/water interface. These techniques are extended to investigate the hydrolysis process of spreading lipid monolayer catalyzed by different enzymes, phospholipases A2, C and D, respectively. Synchrotron X-ray diffraction and infrared reflection absorption spectroscopy are able directly to give the structural information of the assembled monolayer, interfacial activity of amphiphiles and their components at the interface. Microscopic technique such as Brewster angle microscopy (BAM), fluorescence microscopy (FM) can be used to trace the morphological changes dynamically as the spreading lipid monolayer is hydrolyzed at the air/water interface. We summary here some latest progress in this filed and give a brief review over the hydrolysis features of phospholipid monolayer catalyzed by different enzymes. It is attempted to establish a model of membrane hydrolysis process in order to better understand the mechanism of membrane metabolism and signal transduction in a living system.