Peroxidase biological role

List the reactive oxygen species that are generated during electron transport. Explain why oxygen is a potentially toxic substance. Summarize the reactions and the biological roles of superoxide dismutase, catalase, and the peroxidases. 

Oxidation of sulfides catalyzed by haloperoxidases has been reviewed [74]. The natural biological role of haloperoxidases is to catalyze oxidation of chloride, bromide, or iodide by hydrogen peroxide. Three classes of haloperoxidases have been identified (i) those without a prosthetic group, found in bacteria, (ii) heme-containing peroxidases such as chloroperoxidase (CPO), and (iii) vanadium-containing peroxidases. 

Siegel S.M. (1957) Non-enzymic macromolecules as matrices in biological synthesis. The role of polysaccharides in peroxidase catalyzed lignin polymer formation from eugenol // J. Amer. Chem. Soc. V. 79. P. 1628-1632... 

He teaches courses in bioorganic and bioinorganic chemistry (in particular on the role of metals in biology and on the iron-heme enzymes such as peroxidases and cytochromes P-450 monooxygenases). 

Role of Neighboring Polysaccharide Molecules in Determining the Orientation of Tyrosine Residues During Coupling. These considerations suggest a third possible explanation for the exclusive formation of isodityrosine in the plant cell wall in vivo that the neighboring structural molecules of the wall constrain extensin to prevent dityrosine formation. This would mean that the biologically relevant substrate for peroxidase in the plant cell wall is not naked extensin but extensin complexed with another wall component, possibly an acidic polysaccharide to which the extensin would bind ionically. 

The only biological function which has been repeatedly confirmed is the role of peroxidases in lignin monomer polymerization (1). But even in this case, the role of the various isozymes is not yet clear, although anionic, cell wall bound peroxidases generally seem to be involved in lignification... 

Kalf, G, Shurina, R., Renz, J. Schlosser, M. (1990) The role of hepatic metabolites of benzene in bone marrow peroxidase-mediated myelo- and genotoxicity. In Witmer, C.M., Snyder, R.R., Jollow, D.J., Kalf, G.F., Kocsis, J.J. Sipes, I.G., eds, Biological Reactive Intermediates IV, New York, Plenum Press, pp. 443-455... 

Hammel KE, Cullen D (2008) Role of fungal peroxidases in biological ligninolysis. Curr Opin Plant Biol 11 349-355... 

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