Volume 5, Number 1, pp. 13-19
Catalytic and mediator-associating properties of glucose oxidase in a liposome medium assayed with methylene blue
G.P. Gorbenko and Y.A. Domanov
Department of Biological and Medical Physics, V.N. Karazin Kharkov National University, 4 Svobody Sq., 61077 Kharkov, Ukraine
A kinetic analysis of glucose oxidation by glucose oxidase has been performed with a view to gain new information on the catalytic properties of the enzyme adsorbed onto the surface of lipid vesicles. The course of the enzymatic reaction has been monitored spectrophotoÂmetrically with the electron transfer mediator methylene blue. Lipid vesicles have been prepared from egg phosphatidylcholine and cetyltrimethylammonium bromide (5 mol %) by the ethanol injection method. Glucose oxidase binding to the lipid bilayer has been detected by perpendicular light scattering and resonance energy transfer measurements with the fluorescent probe pyrene as donor and flavin adenine dinucleotide as acceptor. The ability of the protein to bring about aggregation of lipid vesicles has been demonstrated. The kinetic parameters of glucose oxidase interaction with glucose, dioxygen and methylene blue have been found to undergo insignificant changes upon enzyme association with liposomes.
Keywords: biosensor, glucose oxidase-lipid interactions, glucose oxidation, kinetic analysis, mediators, methylene blue