• Bulletin of the Korean Chemical Society
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• 제22권1호
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• pp.68-76
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• 2001

We have employed chemical modification to identify amino acids essential for the catalytic activity of alliinase (EC 4.4.1.4) from garlic (Allium sativum). Alliinase degrades S-alkyl-L cysteine sulfoxides, causing the characteristic odor of garlic. The activity of alliinase was rapidly and completely inactivated by N-bromosuccinimide(NBS) and slightly decreased by succinic anhydride and N-acetylimidazole. These results indicate that tryptophanyl, lysyl, and tyrosyl residues play an important role in enzyme catalysis. The reaction of alliinase with NBA yielded a characteristic decrease in both the absorbance at 280 nm and the intrinsic fluorescence at 332 nm with increasing reagent concentration of NBS, consistent with the oxidation of tryptophan residues. Kinetic analysis, fluorometric titration of tryptophans and correlation to residual alliinase activity showed that modification of only one residue present on alliinase led to complete inhibition of alliinase activity. To identify this essential tryptophan residue, we employed chemical modification by NBS in the presence and absence of the protecting substrate analogue, S-ethyl-L-cysteine (SEC) and N-terminal sequence analysis of peptide fragment isolated by reverse phase-HPLC. A fragment containing residues 179-188 was isolated. We conclude that Trp182 is essential for alliinase activity.

• Journal of Ginseng Research
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• 제10권1호
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• pp.1-10
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• 1986

인삼의 부산물중에서 박의 활용가능성을 조사하기 위하여 박의 구성성분, ext의 DPPH 환원력, 효모생육에 미치는 영향 및 효모균체내의 amino acid함량등에 미치는 영향등을 조사한 결과를 요약하면 다음과 같다. 박내에는 총당이 43~46%, 조단백이 14~15%, n-BuOH ext함량은 0.18% 였으며 alcohol박의 물ext는 alcohol ext에 비해 약 46%정도의 DPPH환원력이 남아있었으며 박ext를 첨가하고 효모를 배양시켰을 때 효모의 생육에 필요한 영양물질이나 생육을 촉진하는 물질이 박ext내에 존재하고 있다는 것을 알았으며 알콜박의 물추출물을 첨가하여 배양한 효모균체의 amino acid함량이 다른 ext를 첨가한 효모균체보다 많았다. 박에 cellulase를 0.1%, 20분간 처리로 박ext의 수율을 250%정도 증가시킬 수 있었다.

• 농약과학회지
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• 제9권2호
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• pp.113-121
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• 2005

국가차원에서 식품안전 프로그램은 소비자보호와 식인성질환의 예방을 기본요소로 하고 있으며 정부, 식품산업, 소비자가 책임질 일이다. 여기에서는 WHO에서 제안하고 있는 식품안전 프로그램의 원칙을 소개한 다음 식품생산에 사용되는 의도적 첨가물의 잔류기준 설정에서 GAP의 중요성, 국제기구와 국내에서 잔류농약의 기준설정에 활용되고 있는 절차와 차이점을 지적하였다. 결론적으로 잔류농약에 대한 국내기준을 Codex 기준과 조화시키는데 필요한 사항들을 건의하였다.

• 한국미생물·생명공학회지
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• 제22권6호
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• pp.636-642
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• 1994

Essential amino acids involving in the catalytic mechanism of the $\beta$-D-xylosidase of Bacillus stearothermophilus were determined by chemical modification studies. Among various che- mical modifiers tested N-bromosuccinimide (NBS), $\rho$-hydroxymercurybenzoate (PHMB), N-ethylma- leimide, 1-[3-(di-ethylamino)-propyl]$-3-ethylcarbodi-imide (EDC), and Woodward's Reagent K(WRK)inactivated the enzyme, resulting in the residual activity of less than 20%. WRK reduced the enzyme activity by modifying carboxylic amino acids, and the inactivation reacion proceeded in the form of pseudo-first-order kinetics. The double-lagarithmic plot of the observed pseudo-first- order rate constant against the modifier concentration yielded a reaction order of 2, indicating that two carboxylic amino acids were essential for the enzyme activity. The $\beta$-D-xylosidase was also inactivated by N-ethylmaleimide which specifically modified a cysteine residue with a reaction order of 1, implying that one cysteine residue was important for the enzyme activity. Xylobiose protected the enzyme against inactivation by WRK and N-ethylmaleimide, revealing that carboxylic amino acids and a cysteine residue were present at the substrate-binding site of the enzyme molecule.

• Applied Biological Chemistry
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• 제35권1호
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• pp.64-67
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• 1992

두유박에 함유되어 있는 불용성 형태의 단백질을 Aspergillus oryzae가 생산하는 효소를 이용하여 가용성 형태의 단백질로 용출시키기 위하여 효소작용 최적조건으로서 pH, 온도 및 소화시간을 결정한 다음 추출액의 아미노산 조성을 본 결과 두유박 용출을 위한 최적 pH는 7.5, 최적온도는 $50^{\circ}C$이며 12시간의 소화로 70%의 추출율을 보였다. 두유박에서 추출한 수용액의 아미노산 분석결과 methionine, cysteine, lysine 등의 필수아미노산이 두유박으로부터 상당량 분리되었으며 납두를 사용한 추출액보다 코지를 사용한 경우가 더 좋은 결과를 얻을 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.271-275
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• 2007

γ -Glutamyl transpeptidase (EC 2.3.2.2) plays a key role in glutathione metabolism by catalyzing the transfer of the γ -glutamyl residue and hydrolysis of glutathione. The functional residues at the active site of the rat kidney γ -glutamyl transpeptidase were investigated by kinetic studies at various pH, the treatment of diethylpyrocarbonate (DEPC), and photooxidation in presence of methylene blue. An ionizable group affecting the enzymatic activity with an apparent pKa value of 7.1, which is in the range of pKa values for a histidine residue in protein, was obtained by examining the pH-dependence of kinetic parameters. The pH effect on the photoinduced inactivation rate of the enzyme corresponds to that expected for the photooxidation of the free histidine. The involvement of a histidine in the catalytic site of the enzyme was further supported by DEPC modification accompanied by an increase in absorbance at 240 nm, indicating the formation of Ncarbethoxyhistidine. The histidine located at the position of 382 in the precursor of the enzyme is primarily suspected based on the amino acid sequence alignment of the transpeptidases from various organisms.

• Nuclear Engineering and Technology
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• 제53권9호
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• pp.2926-2936
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• 2021

Rare-earth (RE) industries generate a massive amount of radioactive residue containing high thorium concentrations. Due to the fact that thorium is considered a non-economic element, large volume of these RE processed residues are commonly disposed of without treatment. It is essential to study an appropriate treatment that could reduce the volume of waste for final disposition. To this end, this research investigates the applicability of carbon-based adsorbent in separating thorium from aqueous phase sulphate is obtained from the cracking and leaching process of solid rare-earth by-product residue. Adsorption of thorium from the aqueous phase sulphate by carbon-based electrodes was investigated through electrosorption experiments conducted at a duration of 180 minutes with a positive potential variable range of +0.2V to +0.6V (vs. Ag/AgCl). Through this research, the specific capacity obtained was equivalent to 1.0 to 5.14 mg-Th/g-Carbon. Furthermore, electrosorption of thorium ions from aqueous phase sulphate is found to be most favorable at a higher positive potential of +0.6V (vs. Ag/AgCl). This study's findings elucidate the removal of thorium from the rare-earth residue by carbon-based electrodes and simultaneously its potential to reduce disposal waste of untreated residue.

• Journal of Animal Science and Technology
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• 제64권5호
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• pp.911-921
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• 2022

Maximum residue limits (MRL) for pesticides in feed have been set to protect public health and produce safe livestock products. In vivo experiments to establish MRL are essential, as livestock are commonly used to obtain reliable in vivo quantitative information. Here, we aimed to evaluate whether small laboratory animals can replace or reduce monogastric livestock in experiments to quantify pesticide residues in vivo after oral consumption through feed. First, 24 pigs and rats were randomly assigned to four groups and fed 0, 3, 9, or 30 mg/kg of sulfoxaflor. After four weeks, serum, muscle, fat, liver, kidney, and small intestine samples were collected, and sulfoxaflor residues were analyzed using liquid chromatography - tandem mass spectrometry. Sulfoxaflor residues in pig tissues were significantly correlated with those in rat tissues. Model equations were formulated based on the residual sulfoxaflor amount in pig and rat tissues. The calculated and measured sulfoxaflor residues in pigs and rats showed more than 90% similarity. Sulfoxaflor did not affect body weight gain, feed intake, or the feed conversion ratio. Therefore, we concluded that pesticide residue quantification in vivo to establish MRL could be performed using small laboratory animals instead of livestock animals. This would contribute to obtaining in vivo pesticide residue information and reducing large-scale livestock animal experiments.

• Asian-Australasian Journal of Animal Sciences
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• 제30권10호
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• pp.1464-1470
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• 2017

Objective: This study investigated the effect of fermented biogas residue (FBR) of wheat on the performance, serum biochemical parameters, and meat quality in pigs. Methods: We selected 128 pigs (the mean initial body weight was $40.24{\pm}3.08kg$) and randomly allocated them to 4 groups (1 control group and 3 treatment groups) with 4 replicates per group and 8 pigs per pen in a randomized complete block design based on initial body weight and sex. The control group received a corn-soybean meal-based diet, the treatment group fed diets containing 5%, 10%, and 15% FBR, respectively (abbreviated as FBR5, FBR10, and FBR15, respectively). Every group received equivalent-energy and nitrogen diets. The test lasted 60 days and was divided into early and late stages. Blood and carcass samples were obtained on 60 d. Meat quality was collected from two pigs per pen. Results: During the late stage, the average daily feed intake and average daily gain of the treatment groups was greater than that of the control group (p<0.05). During the entire experiment, the average daily gain of the treatment groups was higher than that of the control group (p<0.05). Fermented biomass residue did not significantly affect serum biochemical parameters or meat quality, but did affect amino acid profiles in pork. The contents of Asp, Arg, Tyr, Phe, Leu, Thr, Ser, Lys, Pro, Ala, essential amino acids, non-essential amino acids, and total amino acids in pork of FBR5 and FBR10 were greater than those of the control group (p<0.05). Conclusion: These combined results suggest that feeding FBR could increase the average daily gain and average daily feed intake in pigs and the content of several flavor-promoting amino acids.

• 에너지공학
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• 제27권1호
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• pp.76-80
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• 2018

The objective of this research paper is to discuss the waste coffee residue disposal and its environmental effects on the environment. As we know, coffee is one of the most demand and swallowed beverages in the world, which leads to large quantities of solid waste. Which can be toxic and a lot of environmental problems occur. In developing countries, there is a lack of proper coffee waste residue management. The coffee beans and residues contain several organic compounds. The wastewater from coffee industry emitted several pollutants (highly concentrated) and it contaminates the soil, ground waters, aquatic life, and also human health. Hence it is essential to treat the coffee waste residues. Mean while, oyster shell waste and its disposal also a big environmental challenge in the coastal regions of southeast Korea. In this paper, we focused the treatment of coffee waste residue with oyster shell waste powder. Primarily, oyster shells are calcinated at higher temperatures and investigated the calcined CaO powder as an anti microbic agent to the bacteria presented in coffee waste residues. We successfully applied calcium oxide from oyster shell waste, as an antimicrobic agent.