Hydrogen peroxidase catalyzed

Fig. 22.2. Schematic representation of the enzymatic process involving paracetamol and hydrogen peroxidase catalyzed by peroxidase of the zucchini tissue powder incorporated into the Nujol/graphite electrode.

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. 

HTAC cationic micelles also markedly enhance the CL intensity of fluorescein (FL) in the oxidation of hydrogen peroxide catalyzed by horseradish peroxidase (HRP) [39], However, no CL enhancement was observed when anionic micelles of sodium dodecyl sulphate (SDS) or nonionic micelles of polyoxyethylene (23) dodecanol (Brij-35) were used (Fig. 9). CL enhancement is attributed to the electrostatic interaction of the anionic fluorescein with the HTAC micelles. The local concentration of fluorescein on the surface of the micelle increases the efficiency of the energy transferred from the singlet oxygen (which is produced in the peroxidation catalyzed by the HRP) to fluorescein. This chemiluminescent enhancement was applied to the determination of traces of hydrogen peroxide. The detection limit was three times smaller than that obtained in aqueous solution. 

For example, peroxidase catalyzes the reaction of luminol derivatives with hydrogen peroxide and results in an increase of the CL reaction velocity and CL intensity. Therefore, intense CL can be obtained from the analyte labeled with luminol derivatives after HPLC separation, followed by reaction with peroxidase. 

The reactivity of compounds such as 28 was clearly demonstrated by the peroxidase-catalyzed covalent binding of A -methyW-hydroxyellipticine (27) to proteins (756). Using horseradish peroxidase and hydrogen peroxide, tritiated-27 was converted to the 9-oxoellipticine derivative in the presence of bovine serum albumin (BSA) and human antibovine IgG in vitro. Covalent binding to these proteins was confirmed by gel electrophoresis, combustion, and liquid scintillation analysis. Dissolution of the BSA-ellipticinium derivative with pronase and... 

Miwa GT, Walsh JS, Kedderis GL, et al. The use of intramolecular isotope effects to distinguish between deprotonation and hydrogen atom abstraction mechanisms in cytochrome P-450- and peroxidase-catalyzed N-demethylation reactions. J Biol Chem 1983 258(23) 14445-14449. 

There is huge potential in the combination of biocatalysis and electrochemistry through reaction engineering as the linker. An example is a continuous electrochemical enzyme membrane reactor that showed a total turnover number of 260 000 for the enantioselective peroxidase catalyzed oxidation of a thioether into its sulfone by in situ cathodic generated hydrogen peroxide - much higher than achieved by conventional methods [52],... 

Coulter et al. (1999,2000b) showed that, in vitro, D. vulgaris Rbr has the ability to function as the terminal component of an NADH peroxidase, catalyzing the reduction of hydrogen peroxide to water (Eq. 10.4). 

The heme peroxidases oxidize a variety of structurally diverse substrates by using hydrogen peroxide or hydroperoxides as oxidants, whereby the oxidants are reduced to water or alcohol. In the following, the present state of such peroxidase-catalyzed reactions in organic synthesis is described, which unquestionably is important for preparative work. 

This enzyme [EC 1.11.1.10], also called chloride peroxidase, catalyzes the reaction of hydrogen peroxide with two RH and two Cl to produce two R—Cl and two water molecules. A heme group is one of the cofactors. This enzyme can also catalyze bromination and iodin-ation, but not fluorination. 

This enzyme [EC 1.11.1.8], also known as iodotyrosine deiodase, iodinase, and thyroid peroxidase, catalyzes the reaction of iodide with hydrogen peroxide to produce iodine and two water. The cofactor for this enzyme is heme. M. Morrison (1970) Meth. Enzymol. 17A, 653 and 658. 

The application of CPO, HRP and CiP is limited to sterically unencumbered substrates and all these peroxidases produce the same absolute configuration of the chiral hydroperoxide. To overcome this limitation, the semisynthetic enzyme selenosubtilisin, a mimic for glutathione peroxidase, with the peptide framework of the serine protease subtilisin was developed by Bell and Hilvert. This semisynthetic peroxidase catalyzes the reduction of hydrogen peroxide and hydroperoxides in the presence of 5-mercapto-2-nitrobenzoic acid. It was utilized by Adam and coworkers and Schreier and coworkers for the kinetic resolution of racemic hydroperoxides (equation 17) . The results obtained were very promising. 

Horseradish peroxidase catalyzes the oxidation of ferrocenes into ferricenium cations by hydrogen peroxide according the stoichiometric Eq. (37) (113). 

Four methods have been developed for enzyme immobilization (1) physical adsorption onto an inert, insoluble, solid support such as a polymer (2) chemical covalent attachment to an insoluble polymeric support (3) encapsulation within a membranous microsphere such as a liposome and (4) entrapment within a gel matrix. The choice of immobilization method is dependent on several factors, including the enzyme used, the process to be carried out, and the reaction conditions. In this experiment, an enzyme, horseradish peroxidase (donor H202 oxidoreductase EC 1.11.1.7), will be imprisoned within a polyacrylamide gel matrix. This method of entrapment has been chosen because it is rapid, inexpensive, and allows kinetic characterization of the immobilized enzyme. Immobilized peroxidase catalyzes a reaction that has commercial potential and interest, the reductive cleavage of hydrogen peroxide, H202, by an electron donor, AH2 ... 

B 8. The breakdown of hydrogen peroxide catalyzed by peroxidase is an oxidation-reduction reaction. Study Equation E12.1 and answer the following questions. 

E. J. Allain, L. P. Hager, L. Deng, and E. N. Jacobsen, Highly enantioselective epoxidation of disubstituted alkenes with hydrogen peroxide catalyzed by chloro-peroxidase, J. Am. Chem. Soc. 1993, 115, 4415-4416. 

Bartlett PN, Pletcher D, Zeng J. Approaches to the integration of electrochemistry and biotechnology II. The horseradish peroxidase catalyzed oxidation of 2,4,6-trimethylphenol by electrogenerated hydrogen peroxide. J Electrochem Soc 1999 146(3) 1088-1092. 

In keeping with current trends in immunohistochemistry to develop alternatives to biotin-streptavidin detection methods, a fluorescyl-tyramide amplification system has recently been introduced (FT-CSA). In this procedure peroxidase is associated with a tissue-bound primary antibody by application of a secondary antimouse Ig antibody to which peroxidase has been conjugated. The peroxidase catalyzes the conversion and deposition of fluorescyl-tyramide onto the tissue section. At this point the reaction can be terminated and viewed by fluorescence microscopy, or the signal can be converted to a colorimetric reaction by the sequential application of an anti-fluorsecein antibody conjugated to peroxidase followed by a diaminobenzidine-hydrogen peroxide substrate. 

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... 

The peroxidase-catalyzed oxidation of orf/io-phenylenendiamine by hydrogen peroxide can be used for the synthesis of diaminophenazine, the starting material for the preparation of many dyes (Fig. 6.2b). 

Monzani E, Roncone R, Galliano M, Koppenol WH, Casella L (2004) Mechanistic insight into the peroxidase catalyzed nitration of tyrosine derivatives by nitrite and hydrogen peroxide. Eur J Biochem 271 895-906... 

Phenazine-2,3-diamine (34) Oxidation by Hydrogen Peroxide Catalyzed by Horseradish Peroxidase " ... 

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