* Department of Chemistry, Moscow State University, Leninskie Gory 1, Moscow, 119992 Russia

 E-mail: vit@enz.chem.msu.ru

** Centre of Chemistry and Chemical Engineering, University of Lund, POB 124, Lund, SE 221-00 Sweden

*** Analytical Chemistry, Ruhr University of Bochum, Bochum, D-44780 Germany

 **** Syngenta Biotech, RTP, NC, the United States

 

The results of testing a new enzyme, anionic tobacco peroxidase (TOP), in various amperometric biosensors are summarized. The biochemical and electrochemical properties of the enzyme are briefly characterized. As compared to the commonly used cationic peroxidase from horseradish roots, TOP exhibits a wider optimum stability pH range, higher stability to inactivation with hydrogen peroxide, and higher efficiency in direct electron-transfer processes. The enzyme immobilized by adsorption on graphite is effective for determination of aminophenols and aromatic diamines in a wall-jet electrode system with a detection limit of 10 nM. Being entrapped into a gel of a redox-active polymer (crosslinked polyvinylimidazole with osmium 4,4'-dimethylbipyridinium chloride) on the graphite electrode surface, TOP exhibited sensitivity and stability comparable to those of horseradish peroxidase and a wider linearity range. TOP immobilized on a self-assembled thiol-monolayer modified gold electrodes was superior to horseradish peroxidase in the sensitivity of hydrogen peroxide detection, regardless of the charge of the monolayer. Prospects for the further use of the native enzyme and its genetically engineered non-glycosylated form are discussed.