• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.163-166
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• 2016

Hydrophobicity is the key concept to understand the water plays in protein folding, protein aggregation, and protein-protein interaction. Traditionally, the hydrophobicity of protein is defined based on the scales of the hydrophobicity of residue, assuming that the hydrophobicity of free amino acids is maintained. Here, we explore how the hydrophobicity of constituting amino acids in protein rely on the protein context, in particular, on the total charge and secondary structures of a protein. To this end, we calculate and investigate the hydration free energy of three short proteins based on the integral-equation theory of liquids. We find that the hydration free energy of charged amino acids is significantly affected by the protein total charge and exhibits contrasting behavior depending on the protein total charge being positive or negative. We also observe that amino acids in the ${\beta}-sheets$ display more enhanced the hydrophobicity than amino acids in the loop, whereas those in the ${\alpha}-helix$ do not clearly show such a tendency. And the salt-bridge forming amino acids also exhibit increase of the hydrophobicity than that with no salt bridge. Our results provide novel insights into the hydrophobicity of amino acids, and will be valuable for rationalizing and predicting the strength of water-mediated interaction involved in the biological activity of proteins.

• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.16-22
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• 1996

Amino acids and ribonucleotides were measured for boiled-dried anchovy to determine the effect of 5 kGy γ-irradiation on its quality stability during storage at ambient and cooling (5∼10℃) temperatures for 12 months in a laminated-film package(Polyethylene 10㎛). The anchovy samples contained about 55%(d.b) of total amino acids and about 1%(d.b) of free amino acids. Although there found a significant change(p<0.01) in the content of leucine and lysine immediately sfter irradiation, the overall content of toral amino acids was little changed in stored anchovy even six months after irradiation at cooling conditions. γ-Irradiation caused a significant reduction(p<0.01) in the total content of free amino acids, showing a similar tendency by storage conditions. However, the ribonucleotides. which were 12.00mg/g(d.b) in inosine-5'-monophosphate and 0.38mg/g(d.b) in guanosine-5'-monophospate, were resistant to 5kGy-irradiation. With the lapse of storage time, it was also shown that storage temperature was more influential than irradiation on the contents of amino acids and taste compounds of dried anchovy.

• Journal of Plant Biotechnology
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• 제41권4호
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• pp.229-235
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• 2014

천마는 난초과 식물로서 예로부터 약용으로 사용되어 왔으며, 봄과 가을에 수확을 한다. 본 연구에서는 천마의 수확시기와 자마의 특성에 따른 아미노산의 함량을 조사하였다. 결론적으로 수확시기에 따른 총 아미노산 함량에는 변화가 없었지만 각 아미노산의 함량은 차이가 있음을 확인하였다. 가을에 수확한 천마에서는 아스파라긴이 19%로 함량이 제일 높았으며, 필수 아미노산으로는 발린인 10%를 차지하였다. 봄에 수확한 천마에서는 세린이 23%로 가장 높은 함량을 보였으며, 필수 아미노산 중에는 아르기닌(10%)로 가장 높은 함량을 보였다. 자마의 특성별 아미노산 함량을 조사 했을 때, 유성증식 천마가 무성증식 천마에 비하여 총 아미노산 함량이 높은 것으로 나타났다. 유성증식 천마의 필수 아미노산은 가을에 수확한 무성증식 천마와 함량이 비슷한 것으로 나왔으며, 비필수 아미노산은 봄에 수확한 무성증식 천마와 함량이 비슷한 것으로 나왔다. 본 연구를 통하여서 천마의 다양한 재배 환경에 대한 아미노산 함량의 변화를 알 수 있었으며, 더 나아가 자연 식품 재료로서의 가치가 높아질것으로 판단이 된다.

• 한국환경성돌연변이발암원학회지
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• 제24권2호
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• pp.67-72
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• 2004

To find active components in Ganoderma lucidum, their free amino acid and free amino acid derivatives were analyzed. After extracting with hot water, the extracts were filtrated by three steps. So, supernatants below 10,000 dalton were obtained. Filtrates were derivativated with PITC (phenylthiocarbamyl) derivative reagent and PITC amino acid was obtained. Then, they were analyzed by RP-HPLC. 13 amino acids were analyzed in cultured Korean Nok-kak ji (one of Ganoderma lucidum), 15 amino acids in cultured Korean Ganoderma lucidum, 12 amino acids wild Ganoderma lucidum, 16 amino acids in cultured Taiwan Ganoderma lucidum.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2542-2548
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• 2009

Direct methylation behaviors of 20 amino acids with tetramethylammonium hydroxide (TMAH) were studied under diluted conditions with silica. Amino acid concentration was controlled by dilution with silica ($SiO_2$) and the molar ratios of amino acid/silica were 0.20, 0.50, and 2.0. The molar ratios of amino acid/TMAH (0.51 - 4.64) also varied. It was found that arginine, asparagine, aspartic acid, cysteine, glutamic acid, and glutamine did not generate any directly methylated pyrolysis products, whereas alanine, glycine, isoleucine, leucine, methionine, phenylanaline, valine, and proline generated all the directly methylated pyrolysis products. Tri- and tetra methylated products of lysine consisted of two types. Histidine and threonine hardly generated the partly methylated products. Mono- and dimethylated products of serine, tryptophan, and tyrosine were not observed. Relative intensities of the methylated products varied with the amino acid concentration, TMAH concentration, and pyrolysis temperature. Direct methylation behaviors of amino acids were explained by the structural characteristics of amino acids.

• 대한가정학회지
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• 제20권4호
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• pp.99-105
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• 1982

Changes of free amino acids as taste compunds during the fermentation of cod-roe, Gadus marcrocephlus, were analyzed by a amino acid autoanalyzer. Leucine, lysine, valine, isoleucine and arginine were dominent amino acids in fresh cod-roe extracts, and the amounts of leucine (797.3mg%, on moisture and salt free base), lysine (577.7mg%) and valine(487.4mg%0 were 54.9% of total free amino acids. The contents of methionine, histidine, tyrosine and phenylanine were lower, and aspartic acid, glycine, threonine, glutamic acid and serine were detected trace amount. The free amino acids analyzed in this experiment were not changed in composition but changed in the amounts during 80 days of the fermentation. Total free amino acids were increased until 59 days of fermentation and than decreased gradually.

• Journal of Plant Biology
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• 제4권1호
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• pp.9-11
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• 1961

A comparative investigation of free amino acids content in healthy check and virus diseased leaves of Chinese date tree, Zyzyphus jujuqa Mill var. inermis Rhed, was carried out by authors throughout the growing season of 1959 and 1960 from June to October. The methods of qualitative analysis of free amino acids aplied in this experiment is followed by Moore and Stein. Free amino acids determined in this experiment are shown in Fig. 1 and Table 1. As the figure and the table are shown, three more amino acids such as glutamine, asparagine and histidine are detected in the diseased material. The additional amino acids which are known as diamines in diseased leaves are conspicuous. It is presumed that the diamine might be incresed by the self-reproduction of the virus in cooporation with certain enzymes which are carrying out the protein metabolism in the host protoplast in contrast with the healthy checks which is carrying out normal protein metabolism. From the histological poing of view, the facts of phloem degeneration or necrosis in diseased leaves, it seems to interrupt to move free amino acids from roots to leaves and it possibly takes place an excessive production of NH3 which is diaminated by the metabolism of nitrogen compounds in such conditioned leaves. Therefore, it is also presumed that additional diamino acids are accumulated in diseased leaves. There are no change of amino acids are accumulated in diseased leaves. There are no change of amino acids in both materials of this plant throughout the growing season qualitatively, and this result agress with the paper of Knight.

• Journal of Plant Biology
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• 제6권4호
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• pp.5-10
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• 1963

농촌에서 식용으로 사용하는 두종의 죽순에 대하여 함유하는 아미노산을 생장부위에 따라 정성분석하였다. 대체로 한 종류가 함유하는 아미노산은 5종 내지 15종이었으며 축순의 생장과정에 따라 함유된 아미노산의 종류는 명명 상위하였다. 식용 죽순에 함유된 필수 아미노산의 종류는 4종에서 9종임을 정성분석 할 수 있었다. 식용죽순에 잇어서도 다른 식물성 식품과 같이 영양가치가 있음을 알아 내었다. 선단부 보다 기부에 아미노산의 종류가 많이 분석된 것은 기부에서 부터 질소대사가 촉진되어 간다는 것을 추측케 하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제12권1호
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• pp.139-147
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• 1999

Peptides are formed in the rumen as the result of microbial proteinase activity. The predominant type of activity is cysteine ptoteinase, but others, such as serine proteinases, are also present. Many species of protozoa, bacteria and fungi are involved in ptoteolysis; large animal-to-animal variability is found when proteinase activities in different animals are compared. The peptides formed from proteolysis are broken down to amino acids by peptidases. Different peptides are broken down at different rates, depending on their chemical composition and particularly their N-terminal structure. Indeed, chemical addition to the N-terminus of small peptides, such as by acetylation, causes the peptides to become stable to breakdown by the rumen microbial population; the microorganisms do not appear to adapt to hydrolyse acetylated peptides even after several weeks exposure to dietary acetylated peptides, and the amino acids present in acetylated peptides are absorbed from the small intestine. The amino acids present in some acetylated peptides remain available in nutritional trials with rats, but the nutritive value of the whole amino acid mixture is decreased by acetylation. The genus Prevotella is responsible for most of the catabolic peptidase activity in the rumen, via its dipeptidyl peptidase activities, which release dipeptides rather than free amino acids from the N-terminus of oligopeptides. Studies with dipeptidyl peptidase mutants of Prevotella suggest that it may be possible to slow the rate of peptide hydrolysis by the mixed rumen microbial population by inhibiting dipeptidyl peptidase activity of Prevotella or the rate of peptide uptake by this genus. Peptides and amino acids also stimulate the growth of rumen microorganisms, and are necessary for optimal growth rates of many species growing on tapidly fermented substrates; in rich medium, most bacteria use pre-formed amino acids for more than 90% of their amino acid requirements. Cellulolytic species are exceptional in this respect, but they still incorporate about half of their cell N from pre-formed amino acids in rich medium. However, the extent to which bacteria use ammonia vs. peptides and amino acids for protein synthesis also depends on the concentrations of each, such that preformed amino acids and peptides are probably used to a much lesser extent in vivo than many in vitro experiments might suggest.

• The Korean Journal of Ecology
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• 제18권4호
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• pp.433-440
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• 1995

The constituents and proportions of non-protein free amino acids including canavanine were measured in roots and leaves of legumes, Robinia pseudo-acacia L., Wistaria floribunda L., and Canavalia lineata L. by using high performance liquid chromatography during dormant and fertilizing seasons. in all the three plant species, asparagine was the most abundant amino acid occurring 30％ of total free amino acids, and canavanine was the second most abundant amino acid contributing 10％ of total free amino acids throughout dormant and fertilizing seasons. In dormant season, roots contained 2 to 3 folds of free amino acids including canavanine and asparagine compared to those in fertilizing season. When proportions of asparagine and canavanine to total gree amino acids in various parts of C. lineata were examined in fertilizinng season, the level of asparagine was the highest in roots while that of canavanine was in seeds. On the basis of these results, it is assumed that canavanine appears and functions as a nitrogen-storing compound in roots and leaves throughout the whole life cycle of the investigated plants.