Oxidation of cinnamyl alcohols and aldehydes by a basic peroxidase from lignifying Zinnia elegans hypocotyls.

The xylem of 26-day old Zinnia elegans hypocotyls synthesizes lignins derived from coniferyl alcohol and sinapyl alcohol with a G/S ratio of 43/57 in the aryl-glycerol-beta-aryl ether core, as revealed by thioacidolysis. Thioacidolysis of Z. elegans lignins also reveals the presence of coniferyl aldehyde end groups linked by beta-0-4 bonds. Both coniferyl and sinapyl alcohols, as well as coniferyl and sinapyl aldehyde, are substrates of a xylem cell wall-located strongly basic peroxidase, which is capable of oxidizing them in the absence and in the presence of hydrogen peroxide. This peroxidase shows a particular affinity for cinnamyl aldehydes with kappa(M) values in the mu(M) range, and some specificity for syringyl-type phenols. The affinity of this strongly basic peroxidase for cinnamyl alcohols and aldehydes is similar to that shown by the preceding enzymes in the lignin biosynthetic pathway (microsomal 5-hydroxylases and cinnamyl alcohol dehydrogenase), which also use cinnamyl alcohols and aldehydes as substrates, indicating that the one-way highway of construction of the lignin macromolecule has no metabolic "potholes" in which the lignin building blocks might accumulate. This fact suggests a high degree of metabolic plasticity for this basic peroxidase, which has been widely conserved during the evolution of vascular plants, making it one of the driving forces in the evolution of plant lignin heterogeneity.

[1]  A. Barceló.  The generation of H2O2 in the xylem of Zinnia elegans is mediated by an NADPH-oxidase-like enzyme , 1998, Planta.

[2]  M. R. Hemm,et al.  New routes for lignin biosynthesis defined by biochemical characterization of recombinant ferulate 5-hydroxylase, a multifunctional cytochrome P450-dependent monooxygenase. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[3]  S. Fry,et al.  Action of diverse peroxidases and laccases on six cell wall-related phenolic compounds , 1999 .

[4]  D. Shibata,et al.  Red-brown color of lignified tissues of transgenic plants with antisense CAD gene : wine-red lignin from coniferyl aldehyde , 1994 .

[5]  M. D. De Biasi,et al.  Soluble peroxidase from winter wheat seedlings with phenoloxidase-like activity. , 1990, Plant physiology.

[6]  A. Barceló,et al.  Coniferyl alcohol oxidase activity of a cell-wall-located class III peroxidase , 1999 .

[7]  R. Sederoff,et al.  A Laccase Associated with Lignification in Loblolly Pine Xylem , 1993, Science.

[8]  M. M. Bradford.  A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[9]  V. L. Singleton.  Oxygen with Phenols and Related Reactions in Musts, Wines, and Model Systems: Observations and Practical Implications , 1987, American Journal of Enology and Viticulture.

[10]  Y. Jiang,et al.  Generation of H2O2 during enzymic oxidation of catechin , 1993 .

[11]  L. Davin,et al.  3.18 – The Nature and Function of Lignins , 1999 .

[12]  L. Davin,et al.  Multi-site modulation of flux during monolignol formation in loblolly pine (Pinus taeda). , 1999, Biochemical and biophysical research communications.

[13]  F. Pomar,et al.  Competitive inhibitor-dissected histochemistry of the peroxidase responsible for syringyl lignin biosynthesis in Zinnia elegans xylem , 2000 .

[14]  Geoffrey D. Brown,et al.  Coniferaldehyde derivatives from tissue culture of Artemisia annua and Tanacetum parthenium , 1999 .

[15]  C. Lapierre,et al.  New insights into the molecular architecture of hardwood lignins by chemical degradative methods , 1995 .

[16]  G. McDougall,et al.  Biochemical characterization, molecular cloning and expression of laccases - a divergent gene family - in poplar. , 1999, European journal of biochemistry.

[17]  A. Barceló,et al.  Hydrogen Peroxide Production is a General Property of the Lignifying Xylem from Vascular Plants , 1998 .

[18]  M. Morales,et al.  A basic peroxidase isoenzyme from vacuoles and cell walls of Vitis vinifera. , 1997 .

[19]  R. Sederoff,et al.  Abnormal lignin in a loblolly pine mutant. , 1997, Science.

[20]  A. Barceló,et al.  Lignification in plant cell walls. , 1997 .

[21]  N. Lewis.  A 20(th) century roller coaster ride: a short account of lignification. , 1999, Current opinion in plant biology.

[22]  Pollet,et al.  Structural alterations of lignins in transgenic poplars with depressed cinnamyl alcohol dehydrogenase or caffeic acid O-methyltransferase activity have an opposite impact on the efficiency of industrial kraft pulping , 1999, Plant physiology.

[23]  T. Umezawa,et al.  Coniferyl aldehyde 5-hydroxylation and methylation direct syringyl lignin biosynthesis in angiosperms. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[24]  S. Hawkins,et al.  Purification and Characterization of Cinnamyl Alcohol Dehydrogenase Isoforms from the Periderm of Eucalyptus gunnii Hook , 1994, Plant physiology.

[25]  A. Catesson,et al.  Peroxidase and phenoloxidase activities in mung bean hypocotyl cell walls , 1993 .