Formation of mediated biocatalytic cathodes by electrodeposition of a redox polymer and laccase

Review of Electrochemically Triggered Macromolecular Film Buildup Processes and Their Biomedical Applications

Macromolecular coatings play an important role in many technological areas, ranging from the car industry to biosensors. Among the different coating technologies, electrochemically triggered processes are extremely powerful because they allow in particular spatial confinement of the film buildup up to the micrometer scale on microelectrodes. Here, we review the latest advances in the field of electrochemically triggered macromolecular film buildup processes performed in aqueous solutions. All these processes will be discussed and related to their several applications such as corrosion prevention, biosensors, antimicrobial coatings, drug-release, barrier properties and cell encapsulation. Special emphasis will be put on applications in the rapidly growing field of biosensors. Using polymers or proteins, the electrochemical buildup of the films can result from a local change of macromolecules solubility, self-assembly of polyelectrolytes through electrostatic/ionic interactions or covalent cross-linking between different macromolecules. The assembly process can be in one step or performed step-by-step based on an electrical trigger affecting directly the interacting macromolecules or generating ionic species.

Purification and characterization of a new laccase from the filamentous fungus Podospora anserina

A new laccase from the filamentous fungus Podospora anserina has been isolated and identified. The 73 kDa protein containing 4 coppers, truncated from its first 31 amino acids, was successfully overexpressed in Pichia pastoris and purified in one step with a yield of 48% and a specific activity of 644Umg(-1). The kinetic parameters, k(cat) and K(M), determined at 37 °C and optimal pH are 1372 s(-1) and 307 μM for ABTS and, 1.29 s(-1) and 10.9 μM, for syringaldazine (SGZ). Unlike other laccases, the new protein displays a better thermostability, with a half life>400 min at 37 °C, is less sensitive to chloride and more stable at pH 7. Even though, the new 566 amino-acid enzyme displays a large homology with Bilirubin oxidase (BOD) from Myrothecium verrucaria (58%) and exhibits the four histidine rich domains consensus sequences of BODs, the new enzyme is not able to oxidize neither conjugated nor unconjugated bilirubin.