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

6 pages; International audience; 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 644 U mg-1. The kinetic parameters, kcat and KM, determined at 37 -C and optimal pH are 1372 s-1 and 307 M for ABTS and, 1.29 s-1 and 10.9 lM, 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.