Phenol peroxidases

Takahama, U. Oniki, T. A peroxidase/phenolics/ascorbate system can scavenge hydrogen peroxide in plant cells. Physiol. Plantarum 1997, 101, 845-852. 

Phenolic compounds Phenolic compounds Horseradish peroxidase Phenol 0.025 pM, Phenol 45 pM,... 

Plug flow Horseradish peroxidase Phenol and aromatic amines [76, 83]... 

Coprinus cimreus peroxidase Phenolic waste stream [2]... 

The enzymatic method for determination of cholesterol Is based on that of Klose et al. [15], as modified by Leon and Stasiw [16]. It involves the use of cholesterol stearase to hydrolyse the cholesterol esters In serum to free cholesterol, which Is oxidized to HzCte that In turn forms a qulnonelmlne dye. The reaction is quantitative, so the concentration of the dye formed Is directly proportional to that of cholesterol In the sample. Figure 14.4 Illustrates the function of the SMAC channel used for the determination, in which the reagent stream (cholesterol oxidase, cholesterol stearase, peroxidase, phenol and 4-aminophenazone), the sample and some air are aspirated by the pump and, after mixing in reactor Ri, are Incubated for 4 min in a bath at 37 C, after which the dye Is extracted Into alcohol and sent to the detector, where Its absorbance Is measured at 525 nm. The aqueous phase from the extraction and the cell waste are aspirated by pump P2. The method has fewer and less serious interferences than Its non-enzymatic counterpart. 

The GOD content in tiiese modified enzymes were determined measuring the adsorption by flavin adenine dinucleotide in solutions of the lyophilized products (the solvents used were water and benzene for the PEG- and lipid-modified GOD, respectively) at 450 nm. The enzyme activities of the native and modified GOD s were measured by using a peroxidase/phenol/4-aminoantipynne chromogenic system. The solution (or dispersed medium in the case of the lipid-modified GOD) was 0.1 M potassium phosphate buffer (pH 7, 25°C). 

Oxidoreductases Peroxidases Phenols, anUines, vinyl compounds... 

Biocatalysts (oxidative enzymes) this enzyme system consists of peroxidases, such as manganese peroxidase, Ugnin peroxidase and other peroxidases, phenol oxidases, such as laccases, and various low-molecular-weight agents, such as oxalate and malate. 

The emission yield from the horseradish peroxidase (HRP)-catalyzed luminol oxidations can be kicreased as much as a thousandfold upon addition of substituted phenols, eg, -iodophenol, -phenylphenol, or 6-hydroxybenzothiazole (119). Enhanced chemiluminescence, as this phenomenon is termed, has been the basis for several very sensitive immunometric assays that surpass the sensitivity of radioassay (120) techniques and has also been developed for detection of nucleic acid probes ia dot-slot. Southern, and Northern blot formats (121). 

Aromatic Amines and Phenols. The discovery that sulfaguanidine [57-67-0] was goitrogenic to rats was serendipitous. Many related compounds were then examined, and the aniline moiety was usually present (2,6). Such compounds, as well as resorcinol-like phenols, may act as goitrogens by inhibiting thyroid peroxidases. These are not used clinically. 

Wasserman, B.P, Eiberger, L.L., and Guilfoy, M.P., Effect of hydrogen peroxide and phenolic compounds on horseradish peroxidase-catalyzed decolorization of betalain pigments, J. Food Sci., 49, 536, 557, 1984. 

Phenol, the simplest and industrially more important phenolic compound, is a multifunctional monomer when considered as a substrate for oxidative polymerizations, and hence conventional polymerization catalysts afford insoluble macromolecular products with non-controlled structure. Phenol was subjected to oxidative polymerization using HRP or soybean peroxidase (SBP) as catalyst in an aqueous-dioxane mixture, yielding a polymer consisting of phenylene and oxyphenylene units (Scheme 19). The polymer showed low solubility it was partly soluble in DMF and dimethyl sulfoxide (DMSO) and insoluble in other common organic solvents. 

The peroxidase-catalyzed polymerization of m-alkyl substituted phenols in aqueous methanol produced soluble phenolic polymers. The mixed ratio of buffer and methanol greatly affected the yields and the molecular weight of the polymer. The enzyme source greatly affected the polymerization pattern of m-substituted monomers. Using SBP catalyst, the polymer yield increased as a function of the bulkiness of the substituent, whereas the opposite tendency was observed when HRP was the catalyst. 

Fluorinated phenols, 3- and 4-fiuorophenols, and 2,6-difluorophenol, were subjected to peroxidase-catalyzed polymerization in an aqueous organic solvent, yielding fluorine-containing polymers. Elimination of fluorine atom partly took place during the polymerization to give polymers with complicated structures. 

Various bisphenol derivatives were also polymerized by peroxidase under selected reaction conditions, yielding soluble phenolic polymers. Bisphenol-A was polymerized by peroxidase catalyst to give a polymer soluble in acetone, DMF, DMSO, and methanol. The polymer was produced in higher yields using SBP as a catalyst. This polymer showed a molecular weight of 4 x 10 and a 7g at 154°C. The HRP-catalyzed polymerization of 4,4 -biphenol produced a polymer showing high thermal stability. ... 

We prepared a phenol-containing hyaluronan derivative, which was inter-molecularly coupled by HRP to yield a crosslinked hydrogel (Scheme 27). The sequenhal injection of this hyaluronan derivative and peroxidase formed... 

The degradation of chlorinated phenols has been examined with the white-rot basidiomy-cete Phanerochaete chrysosporium under conditions of nitrogen limitation, and apparently involves both lignin peroxidase and manganese-dependent peroxidase activities (Valli and Gold 1991). 

D. Vaughan, M. V. Cheshire, and B. G. Ord, Exudation of peroxidase from roots of Festuca rubra and its effects on exuded phenolic acids. Plant Soil I60 i53 (1994). 

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