Construction of multilayer thin films of enzymes by means of sugar-lectin interactions

A layer-by-layer deposition of concanavalin A (Con A) and glycoproteins such glucose oxidase (GOx) and horseradish peroxidase (HRP) afforded multilayer thin films on the surfaces of a quartz slide and a platinum electrode, through biospecific complexation of Con A and sugar residues in the glycoenzymes. Lactate oxidase (LOx), which contains intrinsically no sugar chain, was also built into a multilayer assembly by being modified extrinsically with mannose residues. The enzymes formed monomolecular or sub-monomolecular layers in each layer of the multilayer films. Electrochemical measurements using Con A-enzyme multilayer-modified electrodes revealed that the enzymes are catalytically active in the multilayer films. The Con A-enzyme multilayer films are relatively stable against low concentrations of mannose and urea, although the films destructed gradually in high concentrations of urea solutions (>3 M).