Incorporation of hydrophilic protein modified with hydrophobic agent into liposome membrane

The hydrophilic protein-enzyme, alpha-chymotrypsin, can be bound to the liposomal membrane after the preliminary increase in hydrophobicity induced by acylation of protein amino groups with palmitic chloroanhydride. The efficacy of binding depends on the degree of modification. The bound enzyme almost completely preserves its catalytic properties and the ability to interact with a high molecular weight inhibitor. Binding can be performed during both the process of liposome formation and the incubation of a modified enzyme with preformed liposomes. According to ESR and fluorescence spectroscopy, the hydrophobic tail of the modified enzyme is incorporated into the membrane and the protein globule is located on the surface of the membrane. Protein incorportation causes an increase in the amorphous nature of the membrane, and the bound protein is not as mobile as the free protein. The approach discussed can be useful in binding soluble hydrophilic proteins to artificial membranes.