This letter describes a new method for studying the interaction of the membrane-lysing enzyme phospholipase A(2) (PLA(2)) with phospholipid bilayers by simultaneous measurements of enzyme binding and vesicle lysis using surface plasmon resonance (SPR) and permeabilization using surface plasmon field-enhanced fluorescence spectroscopy (SPFS). The PLA(2) inhibitor dimethyl-eicosadienoic acid was incorporated into the surface-bound vesicles and support bilayer in order to study its role in preventing PLA(2)-mediated vesicle lysis. This methodology has a generic applicability for the study of a range of membrane-disrupting agents.