• Journal of Electrochemical Science and Technology
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• v.5 no.1
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• pp.23-31
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• 2014

The DL-norvaline was electrochemically oxidized and deposited on the glassy carbon electrode surface using cyclic voltammetry (CV). The modified electrode was examined for electrochemical oxidation of hydroquinone (HQ) and catechol (CC). It exhibited good electrocatalytic ability towards their oxidation and simultaneous determination in a binary mixture using differential pulse voltammetry (DPV). The peak currents were linear to the concentration of HQ and CC, in the range from $5{\mu}M$ to $100{\mu}M$, and $4{\mu}M$ to $140{\mu}M$, respectively. The determination limits(S/N = 3) for HQ and CC were $1{\mu}M$ and $0.8{\mu}M$, respectively. The obtained modified electrode was applied to simultaneous detection of HQ and CC in water sample.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2001.06a
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• pp.118-119
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• 2001

A Southern-hybridization analysis and size-selected DNA library screening led to the isolation of a 6.3-kbp S. setonii DNA fragment, from which the Cl20-encoding genetic locus was found to be located within a 1.4-kbp DNA fragment. A complete nucleotide sequencing analysis of the 1.4-kbp DNA fragment revealed a 0.84-kbp ORF, which showed a strong overall amino acid similarity to the known high－G＋C gram-positive bacterial mesophilic C120s. The heterologous expression of the cloned 1.4-kbp DNA fragment in E. coli demonstrated that this Cl20 possessed a thermophilic activity within a broad temperature range and showed a higher activity against 3-methy1catechol than catechol or 4-methy-catechol, but no activity against protocatecuate.

• YAKHAK HOEJI
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• v.60 no.2
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• pp.78-84
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• 2016

N-Phenylthiourea derivatives and catechol oxidase receptor complex was studied using molecular mechanics method. The starting structure was adopted from the protein databank and the calculation of energy minimization and molecular dynamics was performed with AMBER package. The molecular dynamics showed that the simulation time span of 20 ns was long enough to observe the interaction profile and stationary ligand-receptor configuration in the complex. The conformation of the ligand was related to the interaction to the receptor and the efficacy was also interpreted in this context.

• Archives of Pharmacal Research
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• v.22 no.2
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• pp.202-207
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• 1999

New series of catechol ether type derivatives 5, 6 have been synthesized and applied to biological tests. Even though it is ap preliminary data, some of our target molecules show the promising result against PDE IV inhibition. SAR and biological studies with studies with synthetic compounds will be discussed in detail.

• Journal of Plant Biology
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• v.33 no.1
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• pp.41-48
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• 1990

Changes in polamine titers during shoot differentiation in Cymbidium sp. (Jungfrau) protocorms were studied in order to investigate the mechanism of shoot differentiation by using auxin-inhibitors(PCIB, TIBA), hormones(GA3, ABA, BA), and phenolic compounds (2,4-dichlorophenol, catechol). The shoot differentiation and propagation of protocorms were promoted by PCIB or 2,4-dichlorophenol, and the growth of differentiated shoot were promoted by TIBA or catechol. In BA-treated protocorms, white or brown protocorms were observed. Putrescine was the most abundant polyamine during the propagation and differentiation processes. As compared with putrescine, spermidine did not show significant changes and spermine was not detected at all. Putrescine titers decreased after a temporary increase, and then again increased in the presence of GA3, ABA, 2,4-dichlorophenol, and then again increased in the presence of GA3, ABA, 2,4-dichlorophenol, catechol, or PCIB. But, in BA-treated protocorms, putrescine level was much lower than spermidine.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.251-252
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• 2022

Chemical crosslinking is the most widely used method for hydrogel preparations. We prepared a hydrogel using chitosan catechol/polyvinyl alcohol and sodium tetraborate decahydrate (Na₂B₄O₇·10H₂O). The formation of hydrogels often presents inconsistent results and issues according to the reaction scale. Therefore, we measured and analyzed the self-healing property and viscoelasticity of hydrogels attributed to scale-up synthesis using a rheometer.

• Applied Biological Chemistry
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• v.41 no.5
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• pp.384-389
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• 1998

The herbicide propanil and its metabolite, DCA were incubated with oxidative catalysts in the presence or absence of humic monomers to evaluate the incorporation of them into humic substances. Propanil and DCA underwent little or no transformation by oxidatve catalysts in the absence of humic monomers. In the presence of humic monomers, the most effective co-substrate for transformation of propanil was syringic acid by laccase and HRP, that of DCA was catechol by laccase and HRP, and protocatechuic acid by birnessite. The transformation of DCA was the highest when it was incubated with catechol at pH 8.0 during 24 hrs by laccase, and with catechol at pH 3.0 during 2 hrs by HRP, and with protocatechuic acid at pH 5.0 during 2 hrs by birnessite. The DCA transformation increased with increasing concentration of humic monomers. The transformation of DCA was increased with about 5 times when it was incubated with lactase and birnessite together than lactase alone, but that of it was not effected when it was incubated with HRP and birnessite together. When DCA was incubated with dissolved organic carbon in the presence of oxidative catalysts, the transformation of it was not increased by laccase and birnessite but increased by HRP.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.104-111
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• 2007

In this study, aniline dioxygenase genes responsible for initial catabolism of aniline in Burkholderia sp. HY1 and Delftia sp. HY99 were cloned and the amino acid sequences were comparatively analyzed, which already have been reported as bacteria utilizing aniline as a sole source of carbon and nitrogen, B. sp. HY1 was found to have at least a plasmid, and the plasmld-cured strain, B. sp. HY1-PC obtained using mitomycin C was tested with wild type strain to investigate whether the former maintained the degradability for aniline. This proved that the aniline oxygenase gene from B. sp. HY1 was located in chromosomal DNA, not in plasmid DNA. Aniline dioxygenase small subunits from B. sp. HY1 and D. sp. HY99 were found, based on 146 amino acids, to share 79% similarity. Notably, ado2 genes from B. sp. HY1 and D. sp. HY99 which were found to be terminal dioxygenase of aniline dioxygenase small subunit showed 99% similarity in the deduced amino acid sequences with tdnA2 of Frateuria sp. ANA-18 and danA2 of D. sp. AN3, respectively. Besides, enzyme assay and amino acid sequence analysis of catechol dioxygenase supported the previous report that B. sp. HY1 might occupy ortho-cleavage pathway using catechol 1,2-dioxygenase, while D. sp. HY99 might occupy catechol 2,3-dioxygenase for meta-cleavage pathway.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.158-163
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• 2015

Fustin comprised >98 and 73.0-86.7% of the total flavonoid content in the bark, and the stems and lignum of Rhus verniciflua, respectively. The butein, fisetin, and sulfuretin content varied between 0.31-2.17, 0.27-3.32, and 0.15-0.80 mg/g on a dry weight basis, respectively, in different parts of Rhus verniciflua. The urushiol content was 5.09-6.29, 55.05-56.30, and 0.38-0.39 mg/100 g on a dry weight basis in the stems, bark, and lignum, respectively. This showed that the bark of the tree had the highest urushiol content. C15:3 (pentadecatrienyl catechol), C15:1 (pentadecenyl catechol), and C15:2 (pentadecadienyl catechol) comprised 63, 33-35, and 2-3% of urushiol congeners in the tree bark, respectively.

• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.259-271
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• 2021

Many bacteria metabolize aromatic compounds via catechol as a catabolic intermediate, and possess multiple genes or clusters encoding catechol-cleavage enzymes. The presence of multiple isozyme-encoding genes is a widespread phenomenon that seems to give the carrying strains a selective advantage in the natural environment over those with only a single copy. In the naphthalene-degrading strain Pseudomonas putida ND6, catechol can be converted into intermediates of the tricarboxylic acid cycle via either the ortho- or meta-cleavage pathways. In this study, we demonstrated that the catechol ortho-cleavage pathway genes (catBICIAI and catBIICIIAII) on the chromosome play an important role. The catI and catII operons are co-transcribed, whereas catAI and catAII are under independent transcriptional regulation. We examined the binding of regulatory proteins to promoters. In the presence of cis-cis-muconate, a well-studied inducer of the cat gene cluster, CatRI and CatRII occupy an additional downstream site, designated as the activation binding site. Notably, CatRI binds to both the catI and catII promoters with high affinity, while CatRII binds weakly. This is likely caused by a T to G mutation in the G/T-N11-A motif. Specifically, we found that CatRI and CatRII regulate catBICIAI and catBIICIIAII in a cooperative manner, which provides new insights into naphthalene degradation.