Abstract
The phospholipase A2 (PLA2) catalyze specially the hydrolysis of the center(sn-2) ester bond of substrate phospholipids. The hydrolysis products of the PLA2 reaction are free fatty acid and lysophospholipid. The fatty acids released by PLA2, such as arachidonic acid (AA) and oleic acid (OA), can be important as stores of energy, but more importantly AA can also function as a second messenger and as the precursor of eicosanoids, which are potent mediators of inflammation and signal transduction. In this thesis, Fourier transform infrared and Langmuir monolayer are utilized to explore the processes of surface pressure and area decrease of lipid monolayer during PLA2 hydrolysis. Our study showed that PLA2 not only hydrolyzed phospholipid but also carried transported free fatty acid away from membrane interface. The free fatty acid transport phenomenum require calcium ion but is fatty acid chain length independent. Naja nigricolius PLA2 decreased surface area of DMPG monolayer but it cannot transport free fatty acid to the subphase. It implied that Naja nigricolius PLA2 transported Lyso PG instead of free fatty acid chain in negative charge lipid membrane. The aforementioned difference renders new potential research of PLA2 in toxic, physical and pharmacology.