• KSBB Journal
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• v.17 no.2
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• pp.158-161
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• 2002

In this study, a prototype fiber-optic biosensor was fabricated using the inhibition of enzyme reaction by organophosphorus compounds to detect organophosphorus compounds, which is nervous toxic material an? is used as chemical weapon and pesticide. Enzyme, substrate, and inhibitor for enzyme reaction were acetylcholinesterase (key enzyme in nervous cell), acetylthiocholine iodide, and paraoxon (a kind of organophosphorus compounds), respectively. The detection principle of sensor is the detection of enzyme reaction inhibited by organophosphorus compounds by the quantitative measurement of acetic acid, which was achieved by absorbance measurement using litmus solution that maximum absorbance band is changed by pH. To fabricate prototype fiber-optic biosensor, high bright LED and photodiode was used as light source and light intensity detector, respectively. From the experimental results using a prototype biosensor, the linear change of sensor signal was obtained in a range of 0-2 ppm inhibitor concentrations. From these results, it was verified that the quantitative measurement of organophosphorus compounds could be achieved fast (within 2 minutes) and accurately by a prototype fiber-optic biosensor.

• Bulletin of the Korean Chemical Society
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• v.21 no.5
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• pp.471-476
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• 2000

Liquid chromatography/mass spectrometry with an atmospheric pressure chemical ionization interface (LC/APCI/MS) is evaluated for the simultaneous determination of carbamate pesticides and organophosphorus pesticides in a single chromatographic analysis. APCI mass spectra of those compounds were obtrained to study their ionization characteristics. APCI provided abundant ions such as protonated molecules and characteristic fragment ions for carbamate pesticides and organophosphorus pesticides. To evaluate the feasibility of the LC/APCI/MS for a routine quantitative analysis, the linearity and repeatability of LC/APCI/MS were examined by measuring standard solution mixtures of five carbamate pesticides and four organophosphorus pesticides over the range of 1 to 100 ㎍/mL. Teh peak areas in chromatograms of characteristic ions for those compounds showed less than 3% of variation from run to run. The standard calibration curves for the nine pesticides show good linearity in the concentration range. The detection limits of the LC/APCI/MS system for those compounds range from 0.006 to 0.2 ng.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.277-277
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• 2005

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.188-197
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• 2001

Organophosphorus acid anhydrolases(OPAA) catalyzing the hydrolysis of toxic organophosphates have been found in a variety of prokaryotic and eukaryotic organisms. Of the several kinds of OPAA that can degrade nerve agents, such as DFP, sarin and soman, a OPAA gene harbored in the chromosomal DNA of Alteromonas haloplanktis strain was subcloned in order to develope an enzymatic degradation method of toxic organophosphorus compounds. For this 1481 bp DNA fragment containing OPAA gene and its flanking regions has been synthesized through PCR using chromosomal DNA of A. haloplanktis strain. After subcloning and subsequent expression, crude OPA anhydrolase was prepared and assayed. It was shown that the OPAA had a very high hydrolytic activity on DFP. The specific activity of the enzyme was 1,110 $\mu$mole.$min^{p-1}.mg^{-1}$ protein. It seemed that OPAA with such a high hydrolytic activity may give a good prospects to its use, as a biodegradation tool, in detoxifying toxic organophosphorus compounds, such as pesticides and chemical stockpiles which are posing a potential threat to the field environment and human health.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.513-522
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• 2019

Catalysts based on organic compounds, transition metal and metal-organic frameworks (MOFs) have been applied to degrade or remove organophosphorus toxic compounds (OPs). During the last 20 years, various MOFs were designed and synthesized to suit application purposes. MOFs with $Zr_6$ based metal node and organic linker were widely used as catalysts due to their tunability for the pore size, porosity, surface area, Lewis acidic sites, and thermal stability. In this review, effect on catalytic efficiency between MOFs properties according to the structure, stability, particle size, number of connected-ligand, organic functional group, and so on will be discussed.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.3
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• pp.89-96
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• 2005

In the present work, production of organophosphorus hydrolase (OPH) that is secreted in periplasmic space of recombinant Escherichia coli was performed for degradation of environmental toxic organophosphate compounds, paraoxon. The optimal conditions for enhancement of OPH production were 1.0 mM isopropyl-${\beta}$-D-thiogalactopytanoside (IPTG), 0.25 mM $Co^{2+}$, and 0.1 mM ethylenediamine tetraacetate (EDTA). Under these culture conditions, the maximum OPH production was $174Unit/L{\cdot}OD$. In addition, 1 mM of paraoxon was completely degraded by OPH. These results can be used as a bioremediation tool for removal of environmental toxic organophosphate compounds remaining in soil and aquatic environment.

• BMB Reports
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• v.34 no.5
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• pp.440-445
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• 2001

Pesticide waste and chemical stockpiles are posing a potential threat to both Vie environment and human health. There is currently a great effort toward developing effective and economical methods for the detoxification of these toxic organophosphates. In terms of safety and economy, enzymatic biodegradation has been recommended as the most promising tool to detoxify these toxic materials. To develop an enzymatic degradation method to detoxify such toxic organophosphorus compounds, a gene encoding organophosphorus acid anhydrolase (OPAA) from genomic DNA of Alteromonas haloplanktis C was subcloned and expressed. The enzyme consists of a single polypeptide chain with a molecular weight of 48 kDa. It demonstrates strong hydrolyzing activity on sarin, an acetylcholinesterase inhibitor. Moreover, its high activity is sustained for a considerable length of time. It is projected that the recombinant OPAA can be applied as an enzymatic tool that can be used not only for the detoxification of pesticide wastes, but also for the demilitarization of chemical stockpiles.

• Korean Journal of Environmental Agriculture
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• v.15 no.2
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• pp.246-261
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• 1996

Organophosphorus pesticides, which are an important part of synthetic pesticides in current use contain sulfur atom in their molecules and can be activated or detoxified by environmental and/or biological metabolism. Among the related metabolic reactions, oxidative processes are particularly important with their final products and the study on the reactive intermediates formed in those reactions is essential to elucidate the metabolic pathways and mechanisms and to understand the toxicological properties. This review dealt with the reactive intermediates formed in various reactions from the structural and mechanistic point of view for organophosphorus pesticides and related compounds.

• Journal of Environmental Science International
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• v.24 no.12
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• pp.1569-1582
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• 2015

The analytical method for 16 organophosphorus pesticides was developed in this study. The 16 organophosphorus pesticides were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS) using on-line solid phase extraction (on-line SPE) with PLRP- S cartridge. Analysis of all analytes in the MS/MS was processed in the electrospray ioni-zation (ESI) positive mode. They are Azinphos ethyl, Chlorfenvinphos, Ethion, Famphur, Phosmet, Phosphamidon, Terbufos, Aspon, Chlorpyrifos-methyl, Crotoxyphos, Dichlofenthi-on, Dicrotophos, Fonofos, Thionazin, Dimethoate and Iprobenfos. Limits of detection (LODs) and Limits of quantification(LOQs) were obtained as 0.8~2.0 ng/L and 2.6~6.4 ng/L, respectively. All compounds were not detected at the 8 sampling points of the raw water and clean water.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.144-153
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• 2021

Organophosphorus nerve agents (OPNAs), including both G- and V-type nerve agents such as sarin, soman, tabun and VX, are extremely neurotoxic organophosphorus compounds. Catalytic bioscavengers capable of hydrolyzing OPNAs are under development because of the low protective effects and adverse side effects of chemical antidotes to OPNA poisoning. However, these bioscavengers have certain limitations for practical application, including low catalytic activity and narrow specificity. In this study, we generated a fusion-hybrid form of engineered recombinant human paraoxonase 1 (rePON1) and bacterial organophosphorus hydrolase (OPH), referred to as GV-hybrids, using a flexible linker to develop more promising catalytic bioscavengers against a broad range of OPNAs. These GV-hybrids were able to synergistically hydrolyze both G-type OPNA analogs (paraoxon: 1.7 ~ 193.7-fold, p-nitrophenyl diphenyl phosphate (PNPDPP): 2.3 ~ 33.0-fold and diisopropyl fluorophosphates (DFP): 1.4 ~ 22.8-fold) and V-type OPNA analogs (demeton-S-methyl (DSM): 1.9 ~ 34.6-fold and malathion: 1.1 ~ 4.2-fold above) better than their individual enzyme forms. Among the GV-hybrid clones, the GV7 clone showed remarkable improvements in the catalytic activity toward both G-type OPNA analogs (kcat/Km (106 M-1 min-1): 59.8 ± 0.06 (paraoxon), 5.2 ± 0.02 (PNPDPP) and 47.0 ± 6.0 (DFP)) and V-type OPNA analogs (kcat/Km (M-1 min-1): 504.3 ± 48.5 (DSM) and 1324.0 ± 47.5 (malathion)). In conclusion, we developed GV-hybrid forms of rePON1 and bacterial OPH mutants as effective and suitable catalytic bioscavengers to hydrolyze a broad range of OPNA analogs.