Abstract
A unique peroxidase isoenzyme, cationic cell-wall-peroxidase (CWPO-C), from poplar oxidizes sinapyl alcohol, ferrocytochrome c and synthetic lignin polymers. It was suggested that Tyr-177 and Tyr-74 on the protein surface are considered to be important for the oxidation activities of CWPO-C with a wide range of substrates, including lignin.
In this study, we focused on CWPO-C homolog genes of Arabidopsis thaliana, and these T-DNA mutant lines were analyzed. Within the 7 mutant lines, lignins in mutant line 6 and 7 were reduced by 12.6% and by 15.9% compared to wild type, respectively. These mutant lines are defective in the genes encoding peroxidase carries Tyr-177 and Tyr-74. Moreover, yield of DFRC monomers were increased in these mutant lines, compared to other mutants. These results suggest that peroxidase carries Tyr-177 and/or Tyr-74 has an impact on the amount of lignin and lignin assembly in the cell walls.
