Phenols, peroxidase-catalyzed oxidation

In recent years, numerous applications of such peroxidase-catalyzed oxidative coupling of phenols and aromatic amines have been reported (Table 7). These peroxidase-catalyzed biotransformations lead to modified natural products with high biological activities [110-118]. Several examples have also been described for the oxidative coupling of phenols with peroxidases and other oxidative enzymes from a variety of fungal and plant sources as whole cell systems... 

Glucose (65) kits Commercial kits are based on the enzymatic process shown in equation 16, followed by a chromogenic oxidation process catalyzed by peroxidase, similar to equation 27, involving 4- aminoantipyrine (81) and a phenol or aniUne derivative, leading to a quinoneimine dye. Among the latter aromatic substrates in use are A -ethyl-Al-(2-hydroxy-3-sulfopropyl)-3, 5- dimethoxyaniline (92) , phenol , p-hydroxybenzoic acid and p-hydroxybenzenesidfonate other chromogenic reactions are peroxidase-catalyzed oxidation of iV,iV,iV, iV -tetramethyl-p-phenylenediamine (89) and D-ditoluidine (93) . d... 

Fig- 6-1 Some examples of peroxidase-catalyzed oxidations of phenols and naphtols in (d), R1 represents a hydrogen or a bromine atom and R2 a hydrogen, methyl, or carboxymethyl groups... 

Huang Q, Weber WJ Jr (2004) Interactions of soil-derived dissolved organic matter with phenol in peroxidase-catalyzed oxidative coupling reactions. Environ Sci Technol 38 338-344... 

In this study, the kinetics of horseradish peroxidase-catalyzed oxidation of p-cresol (4-methylphenol) is evaluated in a number of representative water-miscible organic solvents. Cresol is one of the most common phenols used in the phenolic resin industry (X) and is an excellent substrate of peroxidase (JL2.). The stoichiometry of peroxidase catalysis is described in Equation 1. The predominant products in aqueous solutions are... 

Perhaps the most well-known peroxidase-catalyzed reactions are those involving electron transfer, in which an aromatic substrate is oxidized in a mono-electronic oxidation up to its mono-radical, Eq. (1), which is capable of participating further in a variety of non-enzymatic reactions such as disproportionation, polymerization and electron transfer. These types of reactions are very common during the peroxidase-catalyzed oxidation of phenols and, in some cases, during the oxidation of alkaloids. For example, peroxidase is capable of dimerizing jatrorrhizine (IV) to 4,4 -bis-jatrorrhizine (V) in the presence of H2O2 (Scheme III) [50]. 

As is the case for other phenols, the peroxidase-catalyzed oxidation of (+)-catechin involves a one-electron oxidation [36] and yields unstable... 

A new class of polyaromatics was synthesized by peroxidase-catalyzed oxidative copolymerization of phenol derivatives with anilines. In the case of a combination of phenol and o-pheneylenediamine, FT-IR analysis showed the formation of the corresponding copolymer.75... 

Peroxidase-catalyzed oxidative coupling of phenols proceeds rapidly in aqueous solutions, furnishing oligomeric compounds. However, mixtures of organic solvents and water are used to better control the quality of the polymer. 

The peroxidase-catalyzed oxidative polymerization of phenols proceeds fast in aqueous solutions, giving rise to the formation of oligomeric compounds. However,... 

Table 16.3-7. Substrates and products of peroxidase - catalyzed oxidative di- and oligomerizations of phenols.

Peroxidase-Catalyzed Oxidative Coupling of Phenols in the Presence of Geosorbents... 

Phenolic polymers and phenol-formaldehyde resins are of great commercial interest for a number of electronic and industrial applications (7). However, there have been serious concerns regarding their use due to various toxic effects of formaldehyde and harsh synthesis environments (2). Peroxidase-catalyzed oxidative polymerization of phenol and substituted phenols provides an alternate route for the synthesis of phenolic polymers (3,4), The increased interest in this type of enzyme-based polymerization is mostly due to its environmental compatibility and potential for producing industrial polymers in high yield (5). 

The peroxidase-catalyzed oxidative coupling of phenols proceeds rapidly in aqueous solution, giving rise to the formation of oligomeric compounds that, unfortunately, have not well been characterized, as most of them demonstrate a low solubility towards common organic solvents and water. In 1987, the enzymatic synthesis of a new class of phenolic polymer was first reported [15], whereby an oxidative polymerization of p-phenylphenol, using HRP as catalyst, was carried out in a mixture of water and water-miscible solvents such as 1,4-dioxane, acetone. 

So far, most peroxidase-catalyzed oxidative polymerizations have been carried out using the enzyme horseradish peroxidase (HRP). Another useful peroxidase that catalyzes the oxidative polymerization of phenols is soybean peroxidase (SBP). While the use of either HRP or SBP may often lead to similar products and results [77], the enzyme activity, yield, and molecular weight of the resulting polymers can also sometimes depend strongly on the type of enzyme used for the polymerization process. For example, SBP was foimd to be superior to HRP for the efficient polymerization of bisphenol A [140], but the polymerization of phenol with SBP afforded... 

The first chapter by Reihmann and Ritter reviews the recent developments of peroxidase-catalyzed oxidative polymerization of phenol and derivatives with a phenolic OH group. The importance of enzymatic polymerization in general is emphasized. Properties of product polyphenols, characteristics of the enzyme catalysis, and significance of the process and the product are discussed. The second chapter by Uyama and Kobayashi is concerned with the oxidative polymerization of polyphenols, which are compounds containing more than two phenolic OH groups. These compounds include catechols and flavonoids... 

A similar system to that for dicarboxylic acids has been described by Akazawa and Conn (1958) for pyridine nucleotides. Chance (1951) had shown that DPNH was a hydrogen donor for the peroxidatic activity of the enzyme, albeit not a very effective one. Akazawa and Conn found that an oxidatic reaction was also catalyzed by peroxidase if manganous ions and a monohydric phenol were present. In its sensitivity to catalase, copper salts, and cyanide, this system closely resembles the classical peroxidase-catalyzed oxidations. Although these investigators did not analyze their system in the terms put forward by Yamazaki, they found that oxidogenic donors were stimulatory and redogenic donors inhibitory in this reaction. 

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