Enzyme-substrate interaction of phospholipase A2 (Naja naja oxiana) with phospholipids has been studied. Spin-labeled palmitic and stearic acids, 1-O-spin-labeled acyl-, 2-O-spin-labeled acylphosphatidyl choline and spin-labeled phosphatidyl-myo-inositol were used for this purpose. This method did not reveal hydrofobic fat-protein interaction. Phospholipase interacts only with the near lipid monolayer of liposomes and vesicles. Being formed lysophosphatidyl choline and fat acids lead to destruction of vesicles, but phospholipase renders stabilization effect.