Immobilization of enzymes on lipid bilayers on a metal support allows study of the biophysical mechanisms of enzymatic reactions

We developed a glucose minisensor based on immobilization of the avidin-glucose oxidase (A-GOX) complex on biotinylated bilayer lipid membranes formed on a metal support (s-BLM). The immobilization of the A-GOX complex on a lipid bilayer was controlled by means of the electrostriction method which allows us to determine the changes in membrane capacitance C, the elasticity modulus in the direction perpendicular to the s-BLM surface E(perpendicular to), and the trans-membrane potential Delta phi(m). The binding of the A-GOX complex to the s-BLM resulted in a decrease in C, increase in E(perpendicular to) and increase in Delta phi(m), suggesting that A-GOX represents a negatively charged complex which increases membrane ordering. Using the simple amperometric method we studied glucose oxidation by GOX and determined several important constants of the enzymatic reaction.