• Analytical Science and Technology
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• 제16권2호
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• pp.152-158
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• 2003

This study was conducted to evaluate two sample digestion procedures and instrumental determination parameters for analysis of lead in bone. Amputated human legs were treated by acid digestion or microwave dissolution prior to spectrometric analysis. Inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrometry (GF-AAS) were used for determining bone lead levels. Recovery efficiencies using standard reference material from acid digestion measured by ICP-MS were in good agreement with those of the certified value, but in cases of acid digestion by GF-AAS and microwave digestion by both two methods, recovery underestimated and overestimated, respectively. For the bone samples, the lead concentrations obtained by ICP-MS after acid digestionwere in good agreement with those by GF-AAS (correlation coefficient = 0.983), but GF-AAS gave systematically higher values than ICP-MS. While a good agreement between two analytical methods after microwave digestion was also obtained (correlation coefficient = 0.950), bone lead concentrations from microwave were relatively higher than those from acid digestion. In conclusion, the use of the simple nitric acid digestion procedure at an ambient temperature coupled to ICP-MS seems to be efficient for the determination of lead in bone in consideration for both the convenience and validity.

• KSBB Journal
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• 제19권6호
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• pp.489-493
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• 2004

The hydrolysis characteristics of various fatty acids composing the fish oil was investigated for function of acyl chain specificities using Lipase-OF 360,000 from Candida cylindracea. The hydrolysis of fatty acids decreased with the increase of the number of carbon and double bond in the fatty acids, in case that the number of double bond and the position of the first double bond from the methyl group of fatty acids were the same. The position of the first double bond was found to be an acyl chain specificity of Lipase-OF 360,000 for the hydrolysis of fish oil. Lipase-OF 360,000 also showed the another acyl chain specificity that the increase of double bond of fatty acids, having the same number of carbon and the position of double bond, brought about the decrease of hydrolysis.

• Journal of Life Science
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• 제18권11호
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• pp.1617-1624
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• 2008

Chitin and chitosan, which is deacetylated form of chitin, are one of the most abundant biomass on the earth. They showed various biological activities including antimicrobial activity, heavy metal chelating, immune system activation, and have very diverse applications in food, pharmaceutical, medicinal, and environmental industry. There have been reported many chitin/chitosan-hydrolyzing enzymes, their structures and genes from three domains, archaea, bacteria, and eukarya. Carbohydrate hydrolyzing enzymes are classified in CAZy (Carbohydrate Active Enzymes) database according to their amino acid sequence similarity. Interestingly, chitinases and chitosanases are classified in various glycosyl hydrolase(GH) families, GH2, GH5, GH7, GH8, GH18, GH19, GH20, GH46, GH48, GH73, GH75, GH80, GH84, and GH85. Here, we review characteristics and structures of chitin/chitosan hydrolyzing enzymes according to glycosyl hydrolase families in order to provide information about gene mining.

• Microbiology and Biotechnology Letters
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• 제26권4호
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• pp.345-351
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• 1998

In an effort to develop a potent system for the production of various dp (degree of polymerization) chitooligosaccharides, 32 enzymes or microbial systems were screened for chitosanolytic acitivity using chitosan as a substrate. The efficiency of each enzyme system was evaluated by the changes of turbidity and viscosity of chitosan solution, the amount of precipitate and the reducing sugar-producing activity in the enzymatic reaction mixture. Based on these assay methods for the chitosanase activity, Bacillus sp. P2l out of 32 screened systems showed highly potent endochitosanase, which was comparable with a commercially available enzyme (E7). Chitooligosaccharides of dp 3-7 were separated by TLC as major enzymatic reaction products, suggesting that the chitosanase from Bacillus sp. P2l be endo-splitting type.

• Journal of Sericultural and Entomological Science
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• 제41권1호
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• pp.48-53
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• 1999

The study was carried out to investigate the effects of hydrolysis conditions such as treatment times and concentrations on the solubility of insoluble sericin using the hydrochloric acid solution. When insoluble sericin was hydrolyzed by HCl solution, the solubility was increased with the higher treatment concentration. As the results of electrophoresis of sericin powder obtained by the HCl treatment, a distinguishable band was not confirmed. Average degree of polymerizations(A.D.P.) of sericin hydrolyzed by HCl solution were about 4.2~5.9 and average molecular weights(M.W.) were about 470~670. The longer hydrolysis time reduced the whiteness of sericin powder. As the results of amino acid analysis, the amino acid compositions of the sericin powder from HCl treatment were sililar to that of insoluble sericin, but Tyr. and Arg. were not detected in the powder obtained by HCl treatment. In DSC analysis, thermal deformation and pyrolysis peak located at near 220$^{\circ}C$ and 330$^{\circ}C$.

• Microbiology and Biotechnology Letters
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• 제30권1호
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• pp.39-45
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• 2002

It was found that the peptides originated from the hydrolysates of silk fibroin have in vitro immunostimulating effects in murine macrophage RAW264.7 cells. The stimulation effects on nitric oxide (NO) production resulted from treatments of acid or enzymatic hydrolysates were measured. The silk fibroin preparation isolated from cocoon was most efficiently digested by acid hydrolysis. Even though the sole treatment of acid hydrolysate stimulated the NO production in dose-dependent pattern, a part of its activity was found to be caused by the contaminated endotoxin, LPS. When each endotoxin-free hydrolysates obtained by filtering it through an ultrafiltration membrane of molecular weight (MW) cut-off 10,000 to eliminate LPS was used, the peptic hydrolysate with lowest degree of hydrolysis showed the highest activity. The fractions of peptic hydrolysate with MW ranges of 1,000∼10,000, 500∼1,000 and below 500 also showed a higher MW-higher activity correlation. From the analyses of amino acid composition of each hydrolysate, it was found that the contents of arginine, lysine, alanine and glycine residues affected the activity level of hydrolysate. The results of this study showed a possibility of utilizing fibroin as a source for immunostimulating (chemopreventive) functional peptides.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 한국퍼지및지능시스템학회 2002년도 추계학술대회 및 정기총회
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• pp.473-477
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• 2002

세포내에서 특정 단백질이 합성되어 이용되는 것을 단백질의 발현이라 한다. 이러한 단백질의발현을 조사하는 작업은 세포내 대사과정을 밝혀내는 데 있어서 매우 중요한 역할을 담당하고 있다. 단백질의 발현을 조사하기 위해서는 세포로부터 추출하여 정제한 단백질이 어떤 단백질인지를 확인하는 작업이 필요한데 현재로써는 확인하고자 하는 단백질 효소로 분해하여 분해된 조각들의 질량을 측정하여 기존에 알려진 단백질들을 분해했을 때 이론상 나을 수 있는 조각들의 무게와 비교하여 가장 근접한 단백질을 찾아내는 질량분석기법(mass Spectrometry)이 널리 사용된다. 그러나 이 방법은 확인하고자 하는 단백질의 아미노산 서열이 알려져 있을 경우에만 사용할 수 있다는 한계점을 가지고 있다. 본 논문에서는 이러한 한계를 계산적인 방법으로 극복하고자 동일단백질을 여러가지 효소로 분해하여 나오는 조각들의 질량을 측정하고 이들을 조합하여 원래 단백질의 아미노산 서열을 알아낼 수 있는 알고리즘을 제안한다.

• KSBB Journal
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• 제24권3호
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• pp.267-272
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• 2009

During a dilute acid hydrolysis, degradation products are formed or liberated by pre-treatment of lignocelluloses depend on both the biomass and the pretreatment conditions such as temperature, time, pressure, pH, redox conditions, and addition of catalysts. In lignocellulosic biomass, sugars can be degraded to furfural which is formed from pentoses and 5-hydroxymethulfurfural (HMF) from hexoses. 5-HMF can be further degraded, forming levulinic acid and formic acid. Acetate is liberated from hemicellulose during hydrolysis. Some decomposed compounds hinder the subsequent bioconversion of the solubilized sugars into desired products, reducing conversion yields and rates during fermentation. In the present work, samples of rapeseed strawwere hydrolyzed to study the optimal pretreatment condition by assessing yields of sugars and decomposed products obtained under different reaction conditions ($H_2SO_4$ 0.5-1.25% (w/w), reaction time 0-20 min and temperature range 150-220 C). A careful analytical investigation of acid hydrolyzate of rapeseed straw has not yet been undertaken, and a well-closed mass balance for the hydrolyzate in general is necessary to verify the productivity and economic predictions for this process.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제2권4호
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• pp.231-238
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• 2004

The conditions are obtained for the decomposition of solid radioactive wastes, including ion exchange resin, zeolite, charcoal, and sludge from nuclear power plant. In the process of decomposing the radioactive wastes was used the microwave acid digestion method with mixed acid. The solution after acid digestion by the following method was colorless and transparent. Each solution was analyzed with ICP-AES and AAS and the recovery yield for 5 different elements added into the simulated radioactive wastes were over $94{\%}$. The elemental analysis of destructive low and medium level radioactive wastes by the proposed microwave acid digestion conditions concerning the chemical characteristics of each radioactive waste are expected to be useful basic data for development of optimal glass formulation.

• Polymer(Korea)
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• 제28권4호
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• pp.291-297
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• 2004

Water-soluble chitosan micro spheres were prepared by emulsification of chitosan solution in mineral oil followed by cross linking reaction with different amount of the cross linking agent (glutraraldehyde), different chitosan concentration. Then, the physicochemical properties such as morphological change by degradation, drug loading efficiency, and drug release profiles were investigated with the drug loaded water-soluble chitosan microspheres. Norfloxacin loaded water-soluble chitosan micro spheres showed excellent drug entrapping capacities without burst release caused by surface bound drug. The absence of the surface bound drug also confirmed by X-ray diffraction study. Degradation and drug release studies showed that the amount of the crosslinking agent played a crucial role for drug loading, release and degradation. The water-soluble chitosan micro spheres showed more sustained drug release profiles with slower degradation and larger particle size by increasing crosslinking agent.