Lignin is an integral cell wall component of all vascular plants. Peroxidases are widely believed to catalyze the last enzymatic step in the biosynthesis of lignin, the dehydrogenation of the p-coumaryl alcohols. As the first stage in identifying lignin-specific peroxidase isoenzymes, the classical anionic peroxidases found in the xylem of poplar (Populus trichocarpa Trichobel) were purified and characterized. Five different poplar xylem peroxidases (PXP 1, PXP 2, PXP 3-4, PXP 5, and PXP 6) were isolated. All five peroxidases were strongly glycosylated (3.6% to 4.9% N-glucosamine), with apparent molecular masses between 46 and 54 kD and pl values between pH 3.1 and 3.8. Two of the five isolated peroxidases (PXP 3-4 and PXP 5) could oxidize the lignin monomer analog syringaldazine, an activity previously correlated with lignification in poplar. Because these isoenzymes were specifically or preferentially expressed in xylem, PXP 3-4 and PXP 5 are suggested to be involved in lignin polymerization.
CITATION STYLE
Christensen, J. H., Bauw, G., Welinder, K. G., Van Montagu, M., & Boerjan, W. (1998). Purification and characterization of peroxidases correlated with lignification in poplar xylem. Plant Physiology, 118(1), 125–135. https://doi.org/10.1104/pp.118.1.125
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