Phenol horseradish peroxidase

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). 

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. 

Regeneration of superoxide during the oxidation of thiols hints at the possible prooxidant effect of these antioxidants. This suggestion was recently confirmed by Mottley and Mason [212] who have showed that superoxide was formed in the oxidation of DHLA by horseradish peroxidase in the presence of phenol. However, DHLA is dithiolic compound and the other mechanisms such as the concerted mechanism, which has been proposed earlier for flavonoids may be realized (Figure 29.6). 

The classic oxidizing systems of human myeloperoxidase and horseradish peroxidase were exploited for their well-known abilities to oxidize phenolic substrates. Under conditions of incubations, the following oxidation pathway was defined (155). Peroxidases are first converted to the oxidized... 

Horseradish peroxidase, as the name implies, is derived from a plant not from humans or animals however, it is readily available and often used as a model to study peroxidase oxidations (42). The classic substrates are phenols, which are oxidized to phenoxy radicals, but aromatic amines are also good substrates. 

Horseradish peroxidase (HRP) an enzyme routinely used in immunohisto-chemistry for labeling antibodies. Histochemichal detection of peroxidase is based on the conversion of aromatic phenols or amines, such as diamino-benzidine (DAB), into water-insoluble pigments in the presence of hydrogen peroxide (H202). 

Tyramide signal amplification This procedure, designated as a catalyzed reporter deposition (CARD) or tyramide signal amplification (TSA), takes advantage of horseradish peroxidase (HRP) from an HRP-labeled secondary antibody to catalyze in the presence of hydrogen peroxide the oxidation of the phenol moiety of labeled tyramine. On oxidation by HRP, activated tyramine molecules rapidly bind covalently to electron-rich amino acids of proteins immediately surrounding the site of the immunoreaction. This allows an increase in the detection of an antigenic site up to 100-fold compared with the conventional indirect method with no loss in resolution. 

Eastmond DA, Smith MT, Ruzo LO, et al. 1986. Metabolic activation of phenol by human myeloperoxidase and horseradish peroxidase. Mol Pharmacol 30 674-679. 

Among other in vitro enzymatic polymerizations that have been studied are the oxidative polymerizations of 2,6-disubstituted phenols to poly(p-phenylene oxide)s (Sec. 2-14b) catalyzed by horseradish peroxidase [Higashimura et al., 2000b] and the polymerization of P-cellobiosyl fluoride to cellulose catalyzed by cellulase [Kobayashi, 1999 Kobayashi et al., 2001],... 

Yu, J., K. E. Taylor, H. Zou, N. Biswas, and J. K. Bewtra, Phenol conversion and dimeric intermediates in horseradish peroxidase-catalyzed phenol removal from water , Environ. Sci. Technol., 28, 2154-2160 (1994). 

Cholesterol assay solution. The stock reagent contains pancreatic cholesterol esterase, microbial cholesterol oxidase, horseradish peroxidase, 4-aminoantipyrine, and phenol. Your instructor will reconstitute the stock reagent by addition of water. 

In this section, the thermal stability of acrylamide gel-immobilized peroxidase will be compared to that of the free enzyme. The free enzyme is assayed in the following manner Dilute 1 mL of the stock horseradish peroxidase (0.1 mg/mL, 15 units/mL) with 299 mL of glass-distilled water. Add 1.0 mL of this diluted enzyme to each of two test tubes. Place one of the tubes in a 60°C water bath for exactly 4 minutes. Allow the other tube to sit at room temperature for the same time interval. Cool the higher-temperature tube to room temperature by placing in a water bath. To each tube add 2.0 mL of the aminoantipyrine-phenol stock solution and 2.0 mL of the H202 solution and mix well. Allow the tubes to sit at room temperature for exactly 3 minutes then immediately read the sl5l0 for each. Record the results in your notebook. 

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

ECL detects horseradish peroxidase-conjugated antibodies through oxidation of luminol, in the presence of hydrogen peroxide and a phenolic enhancer under alkaline conditions. ECL reagents are... 

An automated flow injection analysis (FIA) system for quantifying ethanol was developed using alcohol oxidase, horseradish peroxidase, 4-amino-phenazone, and phenol. A colorimetric detection method was developed using two different methods of analysis, with free and immobilized enzymes. The system with free enzymes permitted analysis of standard ethanol solution in a range of 0.05-1.0 g of ethanol/L without external dilution, a sampling frequency of 15 analyses/h, and relative SD of 3.5%. 

Enzymes of the peroxidase-type which use hydrogen peroxide as the oxidizing species, are capable of performing oxidative coupling of phenolic alkaloids (16). The commercially available horseradish peroxidase as well as peroxidase preparations from potatoes and other sources have been used in conjunction with hydrogen peroxide to perform these transformations. The... 

Cooper VA, Nicell JA. Removal of phenols from a foundry wastewater using horseradish peroxidase. Water Res 1996 30(4) 954-964. 

O Brien AM, O Fagain C. Dye bleaching and phenol precipitation by phthalic anhydride-modified horseradish peroxidase. J Chem Technol Biotechnol 2000 ... 

Buchanan ID, Nicell JA. Model development for horseradish peroxidase-catalyzed removal of aqueous phenol. Biotechnol Bioeng 1997 54(3) 251-261. 

Nicell JA, Saadi KW, Buchanan ID. Phenol polymerization and precipitation by horseradish peroxidase enzyme and an additive. Bioresour Technol 1995 54 5-16. 

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