Enzymes and Antibodies for Biosensors - Studies at the GBF

Abstract

Enzymes and antibodies are key components of most biosensors and have also found wide application in instrumental analysis, e.g. in flow injection analysis [1, 2]. Among the enzymes studied in enzyme sensors, oxidases are of particular importance since they consume oxygen and form hydrogenperoxidetwo species which can easily be monitored by electrochemical or photometric transducers. While many oxidases with a wide range ofsubstrate specificity are commercially available, we have set out to further expand this range by the methods of a) screening of suitable microbial enzymes,and b) by applying the techniques of protein engineering. So far, we have successfully screened a microbial amino acid oxidase, a microbial xanthine oxidase and a microbial acyl-CoA oxidase with unusual substrate specificity. In another part of our work focussed on the "protein design" of biosensor-related proteins, we have solved the structures of two glucose oxidases, purified to homogeneity a thermophilic, hydrogen peroxide forming NADH oxidase, and purified and crystallized a bacterial FMN-dependentluciferase. In the field of immunoreagents for biosensors, we have set out to solve the structure of a pesticide-specific monoclonal antibody. The status and the focus of these investigations will be discussed.