Reorganization of lipid nanocapsules at air–water interface: 3. Action of hydrolytic enzymes HLL and pancreatic PLA 2

Abstract

The action of the hydrolytic enzymes humicola lanuginosa lipase (HLL) and pancreatic phospholipase A 2 (PLA 2) on monolayers formed from lipid nanocapsules (LNC) and model monolayers containing their components, Labrafac ®, Solutol ® and Lipoid ®, is studied by simultaneous measuring the changes in the film area and the surface potential in the “zero order” trough at constant surface pressure ( π). The kinetic models describing the hydrolysis by HLL of the Labrafac, Solutol and their mixtures have been proposed. By using the developed theoretical approach together with the experimental results the surface concentrations of the substrates, hydrolysis products and values of the global kinetic constants were obtained. The comparison between the global kinetic constants in the case of HLL hydrolysis of pure Labrafac, Solutol monolayers and those of the model mixed Labrafac/Solutol monolayers, shows that the rates of hydrolysis are of the same order of magnitude, i.e. an additively of the HLL enzyme action is observed. The composition of the mixed Labrafac/Solutol monolayer, formed after the interfacial LNC destabilization, was estimated.