• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.369-374
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• 2017

The curtailment of production cost is important for the mass production of biosensors. Since horseradish peroxidase, which is a key material of enzyme electrodes for hydrogen peroxide analysis is rather expensive, this has been a limiting factor for fabricating carbon paste based enzyme electrodes. In this paper, the acacia leaf tissue as a zymogen easily obtainable in our living environment was used as an alternative to horseradish peroxidase for developing a hydrogen peroxide sensor and the electrochemical properties were evaluated. Ten or more electrochemical parameters alongside the other experimental results acquired by the potentiostatic method demonstrated that our enzyme electrodes can be used for the quantitative analysis of hydrogen peroxide. This also indicates that acacia leaves can take the place of the marketed peroxidase.

• Journal of the Korean Chemical Society
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• v.56 no.5
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• pp.571-576
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• 2012

A sol-gel derived carbon composite electrodes (CCEs) were fabricated by mixing horseradish peroxidase (HRP), sol of tetraethoxysilane (TESO), and graphite powder. The HRP solution was added to the sol solution of TEOS, and then graphite powder was added to this mixture. The resulting carbon ceramic network effectively encapsulated HRP and shows a catalytic reduction starting at -0.2 V for $H_2O_2$. The optimum conditions for $H_2O_2$determination have been characterized with respect to the enzyme loading ratio and pH. The linear range and detection limit of $H_2O_2$ detection were from 0.2 mM to 2.2 mM and 0.035 mM, respectively. The common electroactive interferences such as ascorbic acid, acetaminophene, and uric acid were not affected upon the response to $H_2O_2$ at the HRP biosensor due to low detection potential.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.768-774
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• 2017

Horseradish peroxidase (HRP) catalyzes the oxidation of aromatic compounds by hydrogen peroxide via insoluble polymer formation, which can be precipitated from the wastewater. For HRP immobilization, poly(lactic-co-glycolic acid) (PLGA) fine carrier supports were produced by using the Nano Spray Dryer B-90. Immobilized HRP was used to remove the persistent 2,4-dichlorophenol from model wastewater. Both extracted (9-16 U/g) and purified HRP (11-25 U/g) retained their activity to a high extent after crosslinking to the PLGA particles. The immobilized enzyme activity was substantially higher in both the acidic and the alkaline pH regions compared with the free enzyme. Optimally, 98% of the 2,4-dichlorophenol could be eliminated using immobilized HRP due to catalytic removal and partly to adsorption on the carrier supports. Immobilized enzyme kinetics for 2,4-dichlorophenol elimination was studied for the first time, and it could be concluded that competitive product inhibition took place.

• Journal of Korean Society on Water Environment
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• v.25 no.1
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• pp.84-89
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• 2009

Our nation's water resources remain susceptible to contamination by phenolic agrichemicals. These compounds can be toxic to a variety of organisms including humans. Their disposal is restricted in many countries with strict limits for acceptable concentrations in drinking water. Enzyme-mediated in situ stabilization has been advocated as an approach for the treatment of phenolic compounds in soils and groundwater. This study reports the development of a new approach to quantify the activity of the HRP enzyme in aqueous systems. The method is based on the coupled processes of energy transfer and enhanced chemiluminescence using a luminol-$H_2O_2$-HRP system. In this study, the effects of solution pH, ionic strength and aqueous concentrations of HRP, $H_2O_2$ and enhancer were evaluated on the p-iodophenol-enhanced, HRP-catalyzed chemiluminescence reaction intensity in Tris-HCl buffer. All assay components were found to affect the maximum chemiluminescene intensity. The calibration curve for HRP showed the linear relationship with maximum light intensity.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2732-2736
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• 2011

In pH 4.2 HAc-NaAc buffer solution, horseradish peroxidase (HRP) catalyzed $H_2O_2$ oxidation of nanosilver to form $Ag^+$. After centrifugation, $Ag^+$ in the supernatant can be measured by graphite furnace atomic absorption spectrophotometry (GFAAS) at the silver absorption wavelength of 328.1 nm. When HRP concentration increased, the $Ag^+$ concentration in the supernatant increased, and the absorption value enhanced. The HRP concentration in the range of 0.84-50 $ng{\cdot}mL^{-1}$ was linear to the enhanced absorption value (${\Delta}A$), with a regression equation of ${\Delta}A$=0.012C+0.11, correlation coefficient of 0.9988, and detection limit of 0.41 $ng{\cdot}mL^{-1}$ HRP. The proposed GFAAS method was used to detect HRP in waste water samples, with satisfactory results.

• Korean Journal of Food Science and Technology
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• v.9 no.2
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• pp.165-169
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• 1977

An apparatus for continuous sterilization of fluids in which heating-up and cooling time are negligible enabled determination of the kinetics of thermal inactivation of peroxidase for the range of temperatures $110{\sim}140^{\circ}C$. The enthalpy of activation was 146.4 kJ/mol; free energy of activation, 113kJ/mol; and the entropy of activation, 82.9J/mol.K. Comparisons of the experimental results with the thermal destruction time curves of microorganisms showed the possibility that the time required to inactivate peroxidase might be taken into account in evaluating thermal processes for commerciel HTST methods.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.297-305
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• 2017

The use of peroxidase in the nitration of phenols is gaining interest as compared with traditional chemical reactions. We investigated the kinetic characteristics of phenol nitration catalyzed by horseradish peroxidase (HRP) in an aqueous-organic biphasic system using n-butanol as the organic solvent and ${NO_2}^-$ and $H_2O_2$ as substrates. The reaction rate was mainly controlled by the reaction kinetics in the aqueous phase when appropriate agitation was used to enhance mass transfer in the biphasic system. The initial velocity of the reaction increased with increasing HRP concentration. Additionally, an increase in the substrate concentrations of phenol (0-2 mM in organic phase) or $H_2O_2$ (0-0.1 mM in aqueous phase) enhanced the nitration efficiency catalyzed by HRP. In contrast, high concentrations of organic solvent decreased the kinetic parameter $V_{max}/K_m$. No inhibition of enzyme activity was observed when the concentrations of phenol and $H_2O_2$ were at or below 10 mM and 0.1 mM, respectively. On the basis of the peroxidase catalytic mechanism, a double-substrate ping-pong kinetic model was established. The kinetic parameters were ${K_m}^{H_2O_2}=1.09mM$, ${K_m}^{PhOH}=9.45mM$, and $V_{max}=0.196mM/min$. The proposed model was well fit to the data obtained from additional independent experiments under the suggested optimal synthesis conditions. The kinetic model developed in this paper lays a foundation for further comprehensive study of enzymatic nitration kinetics.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1263-1269
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• 2005

Horseradish peroxidase, had the phenol degradation rate of 95% in aqueous phase, was covalently immobilized on the surface of reticulated vitreous carbon(RVC) and the degradation of phenol was performed with in situ generated $H_2O_2$-immobilized HRP complex in an electrochemical reactor. The incorporation of carboxylic group on the RVC surface was confirmed by FT/IR spectrometry and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride(EDC) was used for peptide bonds between the carboxylic groups on the RVC surface and amine groups from HRP. The optimal conditions of in situ $H_2O_2$ generation such as concentration($10{\sim}200$ mM) and pH($5.0{\sim}8.0$) of electrolyte, supply of $O_2(10{\sim}50$ mL/min) and applied voltage($-0.2{\sim}-0.8$ volt, vs. Ag/AgCl) from potentiostat/galvanostat were determined by concentration of hydrogen peroxide and current efficiency. It was observed that the RVC immobilized HRP was stable maintaining 89% of the initial activity during 4 weeks. The phenol degradation rate of 86% was attained under the optimal condition of in situ $H_2O_2$ generation.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.470-476
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• 1991

The distribution of peroxidase activity in 9 kinds of cruciferous plants was investigated. Among the plants examined, peroxidase activity was found to be high levels in roots of Chinese cabbage. One kind of peroxidase was purified approximately 56-fold from crude extracts of Chinese cabbage roots. The molecular weight of the enzyme was 50, 000 and consisted oif a single polypeptide chain, as estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and Sephadex G-150 gel column chromatography. The enzyme showed optimum activity at pH 7.0 and $50^{\circ}C$. Phenol and phenol derivatives serves as substrates of the enzyme and Km value for $H_2O_2$ was 1.6 mM toward pyrogallol. The enzyme showed a Soret band at 406 nm and this result indicate that the enzyme contained heme as a prosthetic group. The immunochemical and electrophoretic properties of purified peroxidase from Chinese cabbage were very similar to horseradish peroxidase.

• Bulletin of the Korean Chemical Society
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• v.20 no.11
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• pp.1363-1364
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• 1999