Catalase-peroxidases belong to Class I of the plant, fungal, bacterial peroxidase superfamily, together with yeast cytochrome c peroxidase and ascorbate peroxidases. Obviously these bifunctional enzymes arose via gene duplication of an ancestral hydroperoxidase. A 230-residues long homologous region exists in all eukaryotic members of Class I, which is present twice in both prokaryotic and arch...

Introduction Haem-containing peroxidases from plants, fungi and bacteria are evolutionarily related [ 11. They are built from two structural domains enveloping ferric protoporphyrin IX and contain 11 conserved helices. The two domains, it appears, originated from an early gene duplication event [2]. The general picture of these peroxidases has emerged largely from the crystal structure of mitoc...

A molecular analysis of class III peroxidases from cotton (Gossypium hirsutum L.) was undertaken using the sequence of 12 genes available in databanks. Sequence comparison, phylogenetical analysis, and investigation of expression in organs were performed to characterize this group of peroxidases in cotton. All 12 genes possess the characteristics of class III peroxidases, including three conser...

Density labeling with deuterium oxide, gel electrophoresis, and isopycnic equilibrium sedimentation were used to study the appearance and disappearance of individual peroxidases in the embryos of germinating barley. No detectable label was incorporated into those peroxidases which are present in the embryo of the dry seed and disappear during germination. Deuterium was incorporated into the add...

Lignification is a cell wall fortifying process which occurs in xylem tissue in a scheduled manner during tissue differentiation. In this review, enzymes and the genes responsible for lignin biosynthesis have been studied with an emphasis on lignin polymerizing class III secretable plant peroxidases. Our aim is to understand the cell and molecular biology of the polymerization of lignin especia...

Lignin is the most abundant renewable source of aromatic polymer in nature, and its decomposition is indispensable for carbon recycling. It is chemically recalcitrant to breakdown by most organisms because of the complex, heterogeneous structure. The white-rot fungi produce an array of extracellular oxidative enzymes that synergistically and efficiently degrade lignin. The major groups of ligni...

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 an...

Understanding peroxidase function in plants is complicated by the lack of substrate specificity, the high number of genes, their diversity in structure and our limited knowledge of peroxidase gene transcription and translation. In the present study we sequenced expressed sequence tags (ESTs) encoding novel heme-containing class III peroxidases from Arabidopsis thaliana and annotated 73 full-len...

Ligninolytic fungi accomplish the partial degradation of numerous aromatic organopollutants. Their ability to degrade polycyclic aromatic hydrocarbons (PAHs) is particularly interesting because eukaryotes were previously considered to be unable to cleave fused-ring aromatics. Recent results indicate that extracellular peroxidases of these fungi are responsible for the initial oxidation of PAHs....