Laccase Activity in Azospirillum lipoferum: Substrates and Inhibitors
Azospirillum lipoferum 4B and non-motile A. lipoferum 4T have been isolated from rice rhizosphere. A. lipoferum 4T and A. lipoferum 4Bp, a non-motile form of A. lipoferum 4B, exhibit a laccase activity (Bally R. et al. 1983). Different substrates and inhibitors, which are characteristic of both laccase and tyrosinase activities, have been screened. Oxidation products and enzymatic activity measurements have been carried out using spectrophotometry and HPLC. p- and o-diphenols, p and o-aminophenols and other fungal laccase substrates were oxidized by A. lipoferum 4Bp extracts. Both fungal and Azospirillum laccase activities oxidized aldehydic derivatives and syringic acid. These compounds are known to be precursors in lignins biosyntheses. Tyrosinase inhibitors, like kojic acid or salicylhydroxamic acid, were not effective on Azospirillum laccase activity.
Key Wordslaccase polyphenoloxidase substrates polyphenoloxidase inhibitors tyrosinase syringaldehyde HPLC spectrophotometry
High Performance Liquid Chromatography
Unable to display preview. Download preview PDF.