• Bulletin of the Korean Chemical Society
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• 제21권4호
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• pp.393-400
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• 2000

2,2￠-Dihydroxyazobenzene (DHAB) was attached to poly(ethylenimine) (PEI) to obtain DHAB-PEI. Spectral titration revealed that uranyl, Fe(III), Cu(II), and Zn(II) ion form 1 : 1-type complexes with DHAB attached to PEI. Formation constants for the metal complexes formed by the DHAB moieties of DHAB-PEI were mea-sured by using various competing ligands. The results indicated thatthe concentrations of uranyl, Fe(III), and Cu(II) ions can be reduced to 10 -16 -10 -23 M at p 8 with DHAB-PEI when the concentration of the DHAB moiety is 1 residue M. By using cyanuric chloride as the coupling reagent, DHAB-PEI was immobilized on Sephadex G-25 resin to obtain DHAB-PEI-Seph. Binding of uranyl,Fe(III), Cu(II), and Zn(II) ion by DHAB-PEI-Seph was characterized by using competing ligands. A new method has been developed for characteriza-tion of metal sequestering ability of a chelating resin. Formation constants and metal-binding capacity of two sets of binding sites on the resin were estimated for each metal ion. DHAB-PI-Seph was applied to recovery of metals such as uranium,Fe, Cu, Zn, Pb, V, Mn, and W from seawater. The uranium recovery from seawaterby DHAB-PEI-Seph does not meet the criterion for economical feasibility partlydue to interference by Fe and Zn ions. The seawater used in the experiment was contaminated by Fe and Zn and, therefore, the efficiency of uranium extractionfrom seawater with DHAB-PEI-Seph could be improved if the experiment is carried out in a cleaner sea.

• Journal of Animal Science and Technology
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• 제63권5호
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• pp.1159-1168
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• 2021

Ovotransferrin (OTF), an egg protein known as transferrin family protein, possess strong antimicrobial and antioxidant activity. This is because OTF has two iron binding sites, so it has a strong metal chelating ability. The present study aimed to evaluate the improved immune-enhancing activities of OTF hydrolysates produced using bromelain, pancreatin, and papain. The effects of OTF hydrolysates on the production and secretion of pro-inflammatory mediators in RAW 264.7 macrophages were confirmed. The production of nitric oxide (NO) was evaluated using Griess reagent and the expression of inducible nitric oxide synthase (iNOS) were evaluated using quantitative real-time polymerase chain reaction (PCR). And the production of pro-inflammatory cytokines (tumor necrosis factor [TNF]-α and interleukin [IL]-6) and the phagocytic activity of macrophages were evaluated using an ELISA assay and neutral red uptake assay, respectively. All OTF hydrolysates enhanced NO production by increasing iNOS mRNA expression. Treating RAW 264.7 macrophages with OTF hydrolysates increased the production of pro-inflammatory cytokines and the phagocytic activity. The production of NO and pro-inflammatory cytokines induced by OTF hydrolysates was inhibited by the addition of specific mitogen-activated protein kinase (MAPK) inhibitors. In conclusion, results indicated that all OTF hydrolysates activated RAW 264.7 macrophages by activating MAPK signaling pathway.

• 분석과학
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• 제6권3호
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• pp.307-311
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• 1993

5원자 헤테로고리를 포함하는 열린고리형의 ionophore를 합성하였다. 이 때 합성한 ionophore를 착화제로 이용하여 수용액 중의 $Mg^{2+}$을 염석추출법으로 추출하여 원자 흡광 광도법으로 정량하였다. Acetate 완충용액으로 pH를 4.2로 조절한 $Mg^{2+}$를 포함하는 수용액에 ionophore-AN 용액을 넣어 $Mg^{2+}$-ionophore 착물을 형성시킨 다음, 염석제를 첨가하여 유기층으로 추출하고, 유기층의 착물의 흡광도를 원자 흡광 광도계로서 측정하여 $Mg^{2+}$를 정량하였다. 최적 추출 조건을 조사해 본 결과, 최적 pH는 2.5~5.0이었으며, 염석제인 황산암모늄[$(NH_4)_2SO_4$]의 양은 5g 이상이면 정량적으로 추출되었다. 또한 $Mg^{2+}$과 ionophore의 착물 조성비는 1:2이었다. $Mg^{2+}$의 정량범위는 0.24ppm~2.4ppm이었으며 $Ca^{2+}$이온 및 EDTA의 방해효과가 크게 나타났다.

• BMB Reports
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• 제33권2호
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• pp.172-178
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• 2000

The lipoxygenase was purified 35 fold to homogeneity from the Korean red potato by an ammonium sulfate precipitation and DEAE-cellulose column chromatography. The simple purification method is useful for the preparation of pure lipoxygenase. The molecular weight of the enzyme was estimated to be 38,000 by SDS-polyacrylamide gel electrophoreses and Sepharose 6B column chromatography. The purified enzyme with 2 M $(NH_4)_2SO_4$ in a potassium phosphate buffer, pH 7.0, was very stable for 5 months at $-20^{\circ}C$. Because the purified lipoxygenase is very stable, it could be useful for the screening of a lipoxygenase inhibitor. The optimal pH and temperature for lipoxygenase purified from the red potato were found to be pH 9.0. and $30^{\circ}C$, respectively. The Km and Vmax values for linoleic acid of the lipoxygenase purified from the red potato were $48\;{\mu}M$ and $0.03\;{\mu}M$ per minute per milligram of protein, respectively. The enzyme was insensitive to the metal chelating agents tested (2 mM KCN, 1 and 10mM EDTA, and 1 mM $NaN_3$), but was inhibited by several divalent cations, such as $Cu^{++}$, $Co^{++}$ and $Ni^{++}$. The essential amino acids that were involved in the catalytic mechanism of the 5-lipoxygenase from the Korean red potato were determined by chemical modification studies. The catalytic activity of lipoxygenase from the red potato was seriously reduced after treatment with a diethylpyrocarbonate (DEPC) modifying histidine residue and Woodward's reagent (WRK) modifying aspartic/glutamic acid. The inactivation reaction of DEPC (WRK) processed in the form of pseudo-first-order kinetics. The double-logarithmic plot of the observed pseudo-first-order rate constant against the modifier concentration yielded a reaction order 2, indicating that two histidine residues (carboxylic acids) were essential for the lipoxygenase activity from the red potato. The linoleic acid protected the enzyme against inactivation by DEPC(WRK), revealing that histidine and carboxylic amino acids residues were present at the substrate binding site of the enzyme molecules.

• 대한화학회지
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• 제43권5호
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• pp.522-526
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• 1999

2-Hydroxybenzaldehyde-5-nitro-pyridylhydrazone(2HB-5NPH)를 합성하여 철의 분광학적 정량에 응용하였다. 이 시약은 pH 6.0-7.5 범위에서 철과 반응하여 메탄올 용액에서 매우 안정한 노란색의 1:2킬레이트를 형성한다. 철의 농도범위가 0.05∼2.0 ${\mu}gmL^{-1}$일 때 Beer's law에 적용되고 미량의 철을 분광학적으로 정량하기 위하여 Amberlite XAD-7 비이온성 킬레이트 수지로 채워진 짧은 컬럼을 사용하여 분리과정에 적용하였다. 몇가지 이온들의 방해 효과를 연구하였다. 혼합용액으로부터 철이온의 분리는 완충용액(pH 5.0)과 용리액으로서 0.25M HCl을 가지고 수행하였다.

• Journal of Plant Biotechnology
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• 제39권3호
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• pp.146-153
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• 2012

In this study, the antioxidant property of leaf and callus extracts of five selected in vitro grown Ocimum species (Ocimum sanctum, Ocimum kilimandscharicum, Ocimum gratissimum, Ocimum basilicum, and Ocimum americanum) and their respective callus extracts was investigated. The callus cultures were successfully initiated on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) (1mg L) combined with different concentrations (0.1-0.4 mg L) of kinetin as plant growth regulators. Total phenolic contents were estimated using the Folin-Ciocalteu reagent. 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power, $Fe^{2+}$ chelating activity, and ${\beta}$-carotenelinoleic acid bleaching assays were used to determine the biological effects of the extracts. Interestingly, all the callus extracts exhibited significant (p<0.05) increase in phenolic contents and antioxidant activity. Furthermore, a liner correlation was obtained between the total phenolic contents and free radical scavenging activity ($R^2$ = 0.783). The extracts of leaves and calluses of Ocimum species exhibited activity in all the in vitro antioxidant assays, but its extent was less potent that the positive controls butylated hydroxyl anisole (BHA) and ascorbic acid. A higher accumulation of phenolics in the callus extracts suggests that isolation of high-concentration materials with antioxidant activivity is possible from in vitro callus cultures rather than field-grown plant organs. Furthermore, these extracts may be used as an effective preservative in the food industry.

• 대한화학회지
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• 제36권3호
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• pp.412-418
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• 1992

비수용매인 아세토니트릴 중에서 Cu(Ⅱ)와 1,5,9,13-tetrathiacyclohexadecane[16-ane-$S_4$]의 착물에 대한 전기화학적 거동으로서 직류폴라로그램과 미분펄스폴라로그램으로부터 환원전류의 유형과 가역성을 조사하고, 이들 화합물의 분석적 응용으로서 수용액에 있는 Cu(Ⅱ) 이온을 염석추출법으로 정량하였다. 또한 아세토니트릴 용매 중에서 착물의 안정도 상수를 구하고, 분석적 응용으로 수용액 중의 Cu(Ⅱ)를 염석추출법으로 정량하기 위하여 추출조건, 곧 킬레이트와 염석제의 효과, pH 범위를 구하고 또한 Cu(Ⅱ) 이온을 정량하는데 있어서의 검량성과 공존이온 효과를 조사하였다. 실험결과로부터 환원 과정은 비가역적이었으며 환원전류는 확산지배적임을 알았다. 또한 아세토닐트릴 용매 중에서 착물의 log $K_f$의 값은 3.51이었으며 Cu(Ⅱ) 이온을 정량하는데 있어 공존하는 이온의 영향을 별로 받지 않아 선택성이 좋았으며 본 실험방법에 의한 정량한계는 60ppb 이었다.

• Journal of Audiology & Otology
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• 제23권2호
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• pp.69-75
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• 2019

Background and Objectives: The antioxidant ebselen will be able to limit or prevent the ototoxicity arising from 2-hydroxypropyl-β-cyclodextrin (HPβCD). Niemann-Pick Type C (NPC) disease is a disorder of lysosomal storage manifested in sphingolipidosis. Recently, it was noted that experimental use of HPβCD could partially resolve the symptoms in both animals and human patients. Despite its desirable effect, HPβCD can induce hearing loss, which is the only major side effect noted to date. Understanding of the pathophysiology of hearing impairment after administration of HPβCD and further development of preventive methods are essential to reduce the ototoxic side effect. The mechanisms of HPβCD-induced ototoxicity remain unknown, but the resulting pathology bears some resemblance to other ototoxic agents, which involves oxidative stress pathways. To indirectly determine the involvement of oxidative stress in HPβCD-induced ototoxicity, we tested the efficacy of an antioxidant reagent, ebselen, on the extent of inner ear side effects caused by HPβCD. Materials and Methods: Ebselen was applied prior to administration of HPβCD in mice. Auditory brainstem response thresholds and otopathology were assessed one week later. Bilateral effects of the drug treatments also were examined. Results: HPβCD-alone resulted in bilateral, severe, and selective loss of outer hair cells from base to apex with an abrupt transition between lesions and intact areas. Ebselen co-treatment did not ameliorate HPβCD-induced hearing loss or alter the resulting histopathology. Conclusions: The results indirectly suggest that cochlear damage by HPβCD is unrelated to reactive oxygen species formation. However, further research into the mechanism(s) of HPβCD otopathology is necessary.

• 대한청각학회지
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• 제23권2호
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• pp.69-75
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• 2019

Background and Objectives: The antioxidant ebselen will be able to limit or prevent the ototoxicity arising from 2-hydroxypropyl-β-cyclodextrin (HPβCD). Niemann-Pick Type C (NPC) disease is a disorder of lysosomal storage manifested in sphingolipidosis. Recently, it was noted that experimental use of HPβCD could partially resolve the symptoms in both animals and human patients. Despite its desirable effect, HPβCD can induce hearing loss, which is the only major side effect noted to date. Understanding of the pathophysiology of hearing impairment after administration of HPβCD and further development of preventive methods are essential to reduce the ototoxic side effect. The mechanisms of HPβCD-induced ototoxicity remain unknown, but the resulting pathology bears some resemblance to other ototoxic agents, which involves oxidative stress pathways. To indirectly determine the involvement of oxidative stress in HPβCD-induced ototoxicity, we tested the efficacy of an antioxidant reagent, ebselen, on the extent of inner ear side effects caused by HPβCD. Materials and Methods: Ebselen was applied prior to administration of HPβCD in mice. Auditory brainstem response thresholds and otopathology were assessed one week later. Bilateral effects of the drug treatments also were examined. Results: HPβCD-alone resulted in bilateral, severe, and selective loss of outer hair cells from base to apex with an abrupt transition between lesions and intact areas. Ebselen co-treatment did not ameliorate HPβCD-induced hearing loss or alter the resulting histopathology. Conclusions: The results indirectly suggest that cochlear damage by HPβCD is unrelated to reactive oxygen species formation. However, further research into the mechanism(s) of HPβCD otopathology is necessary.

• Applied Biological Chemistry
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• 제13권1호
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• pp.87-92
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• 1970

본(本) Sericin 분해(分解) 효소(酵素) 강력(强力) 분필균주(分泌菌株) $S_4-1-1$이 생성(生成)하는 Sericinase 는 1. 열(熱)에 대(對)해 안정(安定)하여 $5^{\circ}C$에서 1개월간(個月間) $20^{\circ}C$에서 약(約) 30시간(時間)까지 그 활성(活性)이 지속(持續)되며 2. Fibroin 물질(物質)에 대(對)한 분해력(分解力)은 전연(全然) 인정(認定)되지 않았고 3. EDTA 및 $Ag^{++}$, $Hg^{++}$에 의(依)해 거의 완전실활(完全失活)되며 $Cu^{++}$, $Cd^{++}$에 의(依)해서도 비교적(比較的) 강(强)하게 실활(失活)되였다. 4. 계면활성제(界面活性劑) Peretex N의 혼존시(混存時) 그 활성(活性)이 다소(多少) 촉진(促進)되었다. 이와 같은 Sericin분해효소(分解酵素)를 가잠견(家蠶繭)의 해서(解舒)에 이용(利用)하므로서 현행(現行)되고 있는 자견(煮繭)에 비(比)해 1. 조사성적(繰絲成績) 즉 해서율(解舒率), 생사량비율등(生絲量比率等)이 오히려 우수(優秀)했으며 2, 사조반(絲條班), 소절(小節), 인장강도(引長强度)의 성적(成績) 역시(亦是) 자견(煮繭)에 비(比)해 하등(下等)의 손색(遜色)이 없었다.