• Asian-Australasian Journal of Animal Sciences
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• 제12권8호
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• pp.1298-1309
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• 1999

The nutritional value of protein varies between feedstuffs. It is possible to feed animals using crystalline amino acids as a sole nitrogen source, but in practice only some limiting amino acids are added to the diet. In order to use feedstuffs efficiently, it is important to determine exact amino acid requirements. Reported values differ widely because the requirements are affected by various factors. In this report, therefore, the factors affecting amino acid requirements are reviewed as follows: 1) availability of dietary amino acids, conversion factors of nitrogen to protein, interaction of amino acids, and strain, sex and age of animals; 2) amino acid requirements for maximum performance and maintenance, usefulness of non-essential amino acids; 3) plasma amino acid concentration as a parameter to determine amino acid requirements; and 4) nitrogen excretion to reduce environmental pollution. These factors should be considered, it is to improve the dietary efficiency, which is to reduce excess nitrogen excretion for environmental pollution.

• 한국균학회지
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• 제11권2호
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• pp.85-89
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• 1983

The aims of this study were to investigate various components and their physiological activities of Sarcodon aspratus (Berk.) S. Ito which grows wildly in Korea, belonging to the family Thelephoraceae. The analysis of the powered carpophore of this fungus by TLC and an amino acid autoanalyzer revealed that it contained twenty-one free amino acids and that twenty­two total amino acids were identified in its acid hydrolysate. These amino acids were also quantified.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.103-113
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• 2014

Hydrophobicity is the key concept to understand the role of water in protein folding, protein self-assembly, and protein-ligand interaction. Conventionally, hydrophobicity of amino acids in a protein has been argued based on hydrophobicity scales determined for individual free amino acids, assuming that those scales are unaltered when amino acids are embedded in a protein. Here, we investigate how the hydrophobicity of constituent amino acids depends on the protein context, in particular, on the total charge and secondary structures of a protein. To this end, we compute and analyze the hydration free energy - free energy change upon hydration quantifying the hydrophobicity - 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 net charge being positive or negative. We also observe that amino acids in the central ${\beta}$-strand sandwiched by ${\beta}$-sheets display more enhanced hydrophobicity than free amino acids, whereas those in the ${\alpha}$-helix do not clearly show such a tendency. 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.

• Journal of Nutrition and Health
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• 제3권2호
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• pp.87-94
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• 1970

The amino acid composition of human and cow's milk represents a standard of reference in infantnutrition. The amino acid compositions determined by automatic amino acid analyzer, Yanagimote Model LC-5. Protein in the human and cow's milk were found to be hydrolyzed to yield free amino acids. Qualitative data for free amino acids in the milk are as follows: 1) Amounts of acidic amino acids such as glutamic and aspartic acid in cow's milk were obserbed to be about 2 times compared with human milk and it is considered that the abundance in these amino acids may contribute significantly to the specific flavor of cow's milk. 2) It is much interesting that in the human milk the contents of sulfur-containing amino acids were high comparatively better than cow's milk; cystine was found to be 3 times ana methionine, 2 times. 3) In the human milk a high content of some essential amino acids such as threonine, isoleucine and leucine was demonstrated and a specific flavor sweet amino acids. 4) Large amounts of basic amino acid such as histidine was found to occur in human milk and arginine in cow's milk.

• Asian-Australasian Journal of Animal Sciences
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• 제21권5호
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• pp.701-706
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• 2008

The aim of the present study was to determine the apparent and true digestibilities of amino acids of maize, low tannin sorghum, pearl millet and finger millet in adult caecectomized cockerels. Adult cockerels (n = 60), 25-weeks old, were used in this study of which 30 birds were caecectomized as per a standard method. The apparent digestibilities of amino acids of sorghum were not affected by caecectomy, but were higher for maize, finger millet and pearl millet in caecectomized cockerels. Caecectomy had no influence on the true digestibilities of amino acids of maize, but higher digestibilities were observed for most of the amino acids of sorghum and finger millet in caecectomized cockerels. Caecectomy lowered the true digestibility of cystine, threonine and serine of pearl millet. The apparent digestibilities of amino acids of maize, finger millet and pearl millet were underestimated in intact cockerels. The true digestibilities of most of the amino acids of sorghum and finger millet were underestimated, while those of cystine, threonine and serine of pearl millet were overestimated in intact cockerels. The findings suggest that the amino acid digestibility values of cereal grains determined using caecectomized cockerels might be appropriate and reliable for poultry diet formulations. Moreover, the digestibilities of amino acids of finger millet were inferior to other cereal grains, while those of pearl millet were comparable to maize and sorghum.

• Archives of Pharmacal Research
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• 제2권2호
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• pp.133-144
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• 1979

To investigate constituents of Strobilomyces floccopus (Fr.) Karst. and Coprinus comatus (Fr.) S. F. Gray, free and total amino acids of the two mushrooms were quantitatively analyzed by G. L. C. and an amino acid analyzer. Free amino acids were extracted from both mushrooms with ethanol. Fourtenn free amino acids were detected from the ethanol extract of S. floccopus and fifteen free amino acids from C. comatus by G. L. C. And the dry carphopores of both mushrooms were hydrolyzed with hydrochloric acid and then the total protein amino acids were analyzed by A. A. A. Seventeen total amino acids were detected from each acid-hydrolysate of S. floccopus and C. comatus. Lipids were extracted from the carpophores of S. floccopus and saponified with alcoholic potassium hydroxide. The isolated sterols were subjected to G. L. C. and two sterols were detected. The isolated free fatty acids were methylated with diazomethane and subjected to column chromatography and G. L. C. Eleven saturated and nine unsaturated free fatty acids were detected from the carpophores of S. floccopus. The presence of these nutrient components shows that the two mushrooms can be utilized as edible ones.

• 한국자원식물학회지
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• 제11권1호
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• pp.47-50
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• 1998

For the quantitiative determination of chemical and taste components in black omija(Schizandra nigra Max) and omija(S.chinensis), compositions of free sugars, free amino acids, total amino acids, and minerals were analyzed. Among the total free sugars in black omija and omija, glucose and frutose were major free sugars and sucrose was little amount. The most abundant free amino acid in black imija was histidine and that in imija was serine. The major free amino acid in black omija and omija were histidine, serine, glutamic acid and aspartic acid. The major total amino acids in black omija and omija were glutamic acid, arginine , leucine and histidine. The limiting amino acid of each omija was S-containing amino acids. The abuntdant minerals in black omija and omija were K and Ca.

• 한국연초학회지
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• 제32권2호
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• pp.70-76
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• 2010

A simple and sensitive automatic amino acid analyzer method for the determination of free amino acids in tobacco was described. Sample preparation consisted of a single step of extraction with 0.1 mol HCl at ambient temperature in 60 min by sonication, followed by filtration of an aliquot. Automated amino acid analyzer was used to construct a post-column ninhydrin reaction unit to monitor amino acids separated by liquid chromatography using a series of eluting buffers. By optimization of sample preparation, separation of 19 amino acids was achieved. Limits of quantitation was 0.01 mg/g, coefficients of variation ranged from 0.5 % to 8.9 % and recoveries range from 85 % to 106 %. The method was applied to the analysis of amino acids contents of tobacco leaves in different varieties.

• Nutrition Research and Practice
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• 제3권1호
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• pp.64-71
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• 2009

Amino acids are fundamental nutrients for protein synthesis and cell growth (increase in cell size). Recently, many compelling evidences have shown that the level of amino acids is sensed by extra- or intra-cellular amino acids sensor(s) and regulates protein synthesis/degradation. Mammalian target of rapamycin complex 1 (mTORC1) is placed in a central position in cell growth regulation and dysregulation of mTOR signaling pathway has been implicated in many serious human diseases including cancer, diabetes, and tissue hypertrophy. Although amino acids are the most potent activator of mTORC1, how amino acids activate mTOR signaling pathway is still largely unknown. This is partly because of the diversity of amino acids themselves including structure and metabolism. In this review, current proposed amino acid sensing mechanisms to regulate mTORC1 and the evidences pro/against the proposed models are discussed.

• Applied Biological Chemistry
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• 제15권1호
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• pp.35-40
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• 1972

The contents of free amino acids in deembryod brown rice of two varieties were investigated by amino acid autoanalizer in relation to specific gravity grade. The analytical methods of free amino acid were also discussed. 1) The lower the specific gravity of the unhulled rice the higher the content of total free amino acids in the deembryod brown rice, and the similar trend appears to hold on each amino acids. 2) Main free amino acids were serine+asparagine, glutamic acid, aspartic acid, alanine and valine, and maximum values of them were 7.3, 5.1, 4.0, 3.4, 0.9mg/100g rice, respectively. They consist about 85% of total free amino acids in most cases. 3) The contents of soluble nitrogen and free amino acids appear to be lower in high protein variety (IR 667) than in low protein variety (Jinhung). The percentage of free amino acid nitrogen to soluble nitrogen, however, appears to be higher in high protein variety (IR 667). 4) Alanine was much lower than aspartic acid in IR 667 having Indica blood while alanine appears to be higher than aspartic acid in Jinhung (Japonica rice) suggesting varietal difference in amino acid metabolism. 5) Threonine peak was overlaped with glutamine, and serine was with asparagine in this study.