Impact of inhibiting activity of indole inhibitors on phospholipid hydrolysis by phospholipase A2

The influence of two indole inhibitors on the hydrolysis reaction of l-dipalmitoylphosphatidylcholine (l-DPPC) catalyzed by phospholipase A2 (PLA2) has been studied in the coexistence region using surface pressure as function of time (π–t) and Brewster angle microscopy (BAM) measurements. Similar experiments have been performed with l-DPPC vesicles made by ultrasonication method using transmission electron microscopy (TEM). Comparing the π–t curves and BAM images, which show defected domains after a certain reaction time, as well as TEM images of defected vesicles, one can conclude that the two indole inhibitors have different abilities in reducing the activity of PLA2. The described experiments show that BAM and TEM can be successfully used to study the influence of newly designed inhibitors on the hydrolysis reaction catalyzed by PLA2.