Hydrogen peroxide-peroxidase system

As compounds exhibiting enhancing effects on CL reactions, a variety of phenols, e.g., firefly luciferin and 6-hydroxybenzothiazole derivatives [12,13], 4-iodophe-nol [14], 4-(4-hydroxyphenyl)thiazole [15], 2-(4,-hydroxy-3 -methoxy-benzyli-dene)-4-cyclopentene-l,3-dione (KIH-201) [16], and 2-(4-hydroxyphenyl)-4,5-diphenylimidazole (HDI) and 2-(4-hydroxyphenyl)-4,5-di(2-pyridyl)imidazole (HPI)[17] (Fig. 6A), and phenylboronic acid derivatives, e.g., 4-phenylylboronic acid [18], 4-iodophenylboronic acid [19], and4-[4,5-di(2-pyridyl)-l //-imidazol-2-yl]phenylboronic acid (DPPA) [20] (Fig. 6B), in the luminol/hydrogen peroxide/peroxidase system are well known. Rhodamine B and quinine are used as sensitizers in the CL-emitting reaction between cerium (IV) and thiol compounds. This CL reaction was successfully applied to the sensitive determination of various thiol drugs [21-32],... 

Figure 6 Representative (A) phenol-type and (B) phenylboronic acid-type enhancers for luminol/hydrogen peroxide/peroxidase system. KIH-201, 2-(4 -hydroxy-3 -methoxy-benzylidene)-4-cyclopentene-1,3-dione HDI, 2-(4-hydroxyphenyl)-4,5-diphenylimida-zole HPI, 2-(4-hydroxyphenyl)-4,5-di(2-pyridyl)imidazole DPPA, 4-[4,5-di(2-pyridyl)-lH-imidazol-2-yl]phenylboronic acid).

Henderson JP, Byun J, Mueller DM, Heinecke JW (2001) The Eosinophil Peroxidase-Hydrogen Peroxide-Bromide System of Human Eosinophils Generates 5-Bromouracil, a Mutagenic Thymine Analogue. Biochemistry 40 2052... 

Yoshikawa, S., Kayes, S.G. and Parker, J.C. (1993). Eosinophils increase lung microvascular permeability via the peroxidase-hydrogen peroxide-halide system. Bronchoconstriction and vasoconstriction unaflFected by eosinophil peroxidase inhibition. Am. Rev. Respir. Dis. 147, 914-920. 

Jhoo et al. reported that the oxidation of theaflavin in either DPPH or the peroxidase-hydrogen peroxide model system leads to the generation of theanaphthoqui-none as the major oxidation product. The proposed radical scavenging mechanism of theaflavin is shown in figure 8.14. Theanaphthoquinone is formed through one-electron oxidation. This indicates that the benzotropolone moiety of theaflavin is the active site for scavenging of radicals. ... 

Horseradish peroxidase (HRP) is an archetypal heme peroxidase. It is a nonspecific enzyme used for studying the etfect of various substances on HRP-catalyzed electron-transfer reactions.1 2 For the enzyme activity determinations, many substrates and types of methods are used. One of these methods is lumino 1-dependent chemiluminescence (CL). The combination of the enzyme HRP/hydrogen peroxide (H202) system and a chemiluminescent method of detection allows for information to be obtained both about the result of the process and its course. 

A.R.T.S. Araujo, F. Maya, M.L.M.F.S. Saraiva, J.L.F.C. Lima, J.M. Estela, V. Cerda, Flow system for the automatic screening of the effect of phenolic compounds on the luminol-hydrogen peroxide-peroxidase chemiluminescence system. Luminescence 26 (2011) 571—578. 

They showed that molecular oxygen was a requirement and, in the peanut system, that a hydrogen peroxide generating system was involved. Enzymes which catalysed the reduction of peroxides, such as glutathione peroxidase, reduced a-oxidation and increased the production of D-hydroxypalmitate. This pointed to the existence of a peroxide, 2-hydroperoxypalmitate,... 

One of the most used systems involves use of horseradish peroxidase, a 3-diketone (mosl commonly 2,4-pentandione), and hydrogen peroxide." " " Since these enzymes contain iron(II), initiation may involve decomposition of hydrogen peroxide by a redox reaction with formation of hydroxy radicals. However, the proposed initiation mechanism- involves a catalytic cycle with enzyme activation by hydrogen peroxide and oxidation of the [3-diketone to give a species which initiates polymerization. Some influence of the enzyme on tacticity and molecular... 

Choi H.W. Kim Y.J. Lee S.C. Hong J.K. Hwang B.K. (2007) Hydrogen peroxide generation by the pepper extracellular peroxidase CaP02 activates local and systemic cell death and defense response to bacterial pathogens / / Plant Physiology. V. 145. P. 890-904. 

Katayama, Y. Fukuzumi, T. Enzymic synthesis of three lignin-related dimers by an improved peroxidase-hydrogen peroxide system. Mokuzai Gakkaishi 1978,24,664-667. 

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

The use of hydrogen peroxide as an oxidant is not compatible with the operation of a biocatalytic fuel cell in vivo, because of low levels of peroxide available, and the toxicity associated with this reactive oxygen species. In addition peroxide reduction cannot be used in a membraneless system as it could well be oxidized at the anode. Nevertheless, some elegant approaches to biocatalytic fuel cell electrode configuration have been demonstrated using peroxidases as the biocatalyst and will be briefly reviewed here. 

In this system, choline formed by acetylcholinesterase is oxidized by choline oxidase and the hydrogen peroxide produced is determined using the luminol/peroxidase CL reaction. The sensor has been used for the analysis of Paraoxon and Aldicarb pesticides, with detection limits of 0.75 pg/L and 4 pg/ L, respectively. Recoveries in the range of 81-108% in contaminated samples of soils and vegetables were obtained. 

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