• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.609-615
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• 1994

Fermented traditional soybean paste(doenjang), koji soybean paste by Aspergillus oryzae, natto soybean paste by Bacillus natto and koji & natto soybean paste by Aspergillus oryzae and Bacillus natto were analyzed for compositions of amino acids and contents of nitrogens. Amino type nitrogen was the highest in fermenting for 90 days as $271{\sim}868\;mg/100g$, and its contents were in the order of koji soybean paste>traditional soybean paste>koji & natto soybean paste>natto soybean paste in all samples tested. In compositions of total amino acids, glutamic and aspartic acids were rich in koji soybean paste but big differences were not observed in all samples. But some differences were observed in free amino acid compositions in all samples, that is, glutamic acid, tyrosine, lysine and aspartic acid were detected more abundantly. Sum of free amino acids for 90 days were in order of koji soybean paste>traditional soybean paste>koji & natto soybean paste>natto soybean paste. The ratios of free to total amino acids were $3.28{\sim}19.81%$ for 45 days, but increased to $10.88{\sim}25.10%$ for 90 days, and in order of traditional doenjang>koji doenjang>koji & natto doenjang>natto doenjang. Methionine and histidine showed higher ratios of free to total amino acid but lower in glutamic acid and aspartic acid. These results suggest that koji and traditional soybean paste of having high ratios of free amino acids to free and total amino acids may be more favorable in soybean paste fermentation.

• Korean Journal of Agricultural Science
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• v.9 no.2
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• pp.576-583
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• 1982

The variation of free amino acids during the tomato producing was studied using a tomato variety, Kagome 77. The concentration of free amino acids in fresh and heated pulp, and in puree and paste was analyzed by using automatic amino acid analyzer, Hitachi model KLA-5. 1. A significant difference in decomposition rate of glutamine and asparagine among amide group was recognized. For instance, the glutamine decomposed fast and no glutamine was found in the paste, while 56% of asparagine was found in the paste. 2. The diminishing quantity of glutamic acid among acid group was highest among all free amino acids. The quantity of aspartic acid was next to the glutamine. The percents of glutamic acid and aspartic acid left over were 38% and 24%, respectively. 3. Glycine, alanine, valine, isoleucine and leucine of neutral amino acids tended to be reduced a little during the heating, concentrating process. 4. No apparent variation was found for the lysine and histidine belonging to basic amino acids. while arginine increased a little. 5. Tyrosine, phenylalanine and tryptophane of aromatic group seemed to increase a little during the heating process. But the variations of them during the concentrating process were not recognized. 6. The methionine content, sulfur containing amino acid decreased a little throughout the process. But the decrease of ${\gamma}-amino$ butyric acid of non-protein was not apparently recognized. 7. The amino acid contents of fresh pulp were found as following order: glutamic acid>${\gamma}$-amino butyric acid>glutamine>aspartic acid>asparagine. The amino acid contents of paste were as glutamic acid>${\gamma}$-amino butyric acid>aspartic acid and aspargine. The percent distribution of aromatic and basic amino acids increased, even it was not great. 8. When amino acids were analyzed by Hitachi KLA-5, unknown peak which was never app eared in the fresh pulp before tryptophane was appeared when processed. The peak became greater when heated and concentrated. Later it was known that the peak was not due to lysinoalanine or ornithine.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.121-128
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• 2006

The purified xylanase from Bacillus alcalophilus AX2000 was modified with various chemical modifiers to determine amino acid residues in the active site of the enzyme. Treatment of the enzyme with group-specific reagents such as carbodiimide or N-bromosuccinimide resulted in complete loss of enzyme activity. These results suggested that these reagents reacted with glutamic acid or aspartic acid and tryptophan residues located at or near the active site. In each case, inactivation was performed by pseudo first-order kinetics. Inhibition of enzyme activity by carbodiimide and N-bromosuccinimide showed non-competitive and competitive inhibition type, respectively. Addition of xylan to the enzyme solution containing N-bromosuccinimide prevented the inactivation, indicating the presence of tryptophan at the substrate binding site. Analysis of kinetics for inactivation showed that the loss of enzyme activity was due to modification of two glutamic acid or aspartic acid residues and single tryptophan residue.

• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.1887-1892
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• 2008

Novel poly(aspartic acid) derivatives conjugated with L-lysine moieties and their amphiphilic analogs were synthesized and characterized. The chemical structures of these polymers were confirmed using FT-IR and $^1HNMR$ spectroscopy. The physicochemical properties of amphiphilic copolymers were characterized using an electrophonetic light scattering spectrophotometer (ELS) and transmission electron microscopy (TEM). These results indicated a stable nanoparticle formation within aqueous media. These polymers have potential applications in the pharmaceutical and cosmetic fields as delivery vehicles for bioactive molecules.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.311-314
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• 1992

A new monocyclic ${\beta}-lactam$ analogue, sodium (3R,4S)-3-[2-(2-aminothiazol-4-yl)-(Z)-2-methoxyi minoacetamido]-4-methoxymethyl-2-azetidinone-1- sulfonate (3) was synthesized from L-aspartic acid. Starting from L-aspartic acid, (S)-1-benzyl-4-benzyloxycarbonyl-2-azetidinone (7) was synthesized in four steps by following the established procedures and converted into (3R,4S)-3-amino-1-t-butyldimethylsilyl-4-methoxym ethyl-2-azetidinone (13) in six steps. Acylation of the amino group of 13 with $2-amino-{\alpha}$ -(methoxyimino)-4-thiazoleacetic acid, desilylation, and sulfonation with sulfur trioxide-pyridine complex followed by ion exchange afforded sodium (3R,4S)-3-[2-(2-aminothiazol-4-yl)-(Z)-2-methoxyi minoacetamido]-4-methoxymethyl-2-azetidinone-1- sulfonate (3). Antibacterial activities of this ${\beta}$ -lactam compound 3 were, however, found to be quite low compared to cefotaxime.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.315-316
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• 1992

Sodium (3S,4R)-3-[2-(2-aminothiazol-4-yl)-(Z)-2-methoxyi minoacetamido]-4-methoxymethyl-2-azetidinone-1- sulfonate (2) was synthesized in fourteen steps from D-aspartic acid. Starting from D-aspartic acid, (3S,4R)-3-amino-1-t-butyldimethylsilyl-4-methoxym ethyl-2-azetidinone (12) was synthesized in ten steps. Acylation of the amino group of 12 with $2-amino-{\alpha}-(methoxyimino)-4-thiazoleacetic$ acid, desilylation, sulfonation, and ion exchange afforded sodium (3S,4R)-3-[2-(2-aminothiazol-4-yl)-(Z)-2-methoxyi minoacetamido]-4-methoxymethyl-2-azetidinone-1- sulfonate (2). This new ${\beta}-lactam$ compound 2 showed low antibacterial activities.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.140-144
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• 2003

Type Ⅰ signal peptidase is an integral membrane protein that functions to cleave signal peptides from secreted and membrane proteins. The enzyme serves as a potential target for the development of novel antibacterial agents due to its unique physiological properties. Despite being one of the best characterized enzymes, the catalysis of Type Ⅰ signal peptidase still remains controversy over the catalytic serine/lysine dyad mechanism. It appears that the dyad proteases are generally less efficient than the prototypical serine/histidine/aspartic acid triad found in most enzymes, although Type Ⅰ signal peptidase is an exception to this rule. In this paper, we have proposed that Type Ⅰ signal peptidase may act as the serine/lysine/aspartic acid triad cataltytic mechanism. Therefore, the aspartic acid 99 residue in the E. coli signal peptidase was chosen and mutated to an alanine to see if there is any possible role of the aspartic acid in the catalytic function. Type Ⅰ signal peptidase D99A protein was inactive in vitro assay using the procoat synthesized by in vitro transcription translation. However, the mutant was active using a highly sensitive in vivo assay. Pulse-chase experiments show that the replacement of aspartic acid 99 with alanine results in a very unstable signal peptidase molecule. Therefore, we conclude that it is unlikely that the residue is directly involved in catalysis, but rather plays an important role in stabilizing the protein structure.

• Journal of Oral Medicine and Pain
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• v.14 no.1
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• pp.43-55
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• 1989

The need of age estimation for identification was increased by complexity of society, and the tooth was used widely for age estimation because of less individual deviation than the other organ. The age estimation using the tooth had several methods. Recently, the one using the racemization of aminoacid in the tooth was admitted more accurate than the other methods, especially in old age. But, this study was not tried in our country, and I would report the result of experiment about age estimation using racemization of dentine. I selected 40-Whole dentine sample from extracted teeth, those were reserved in natural dried condition for 2 weeks~ 1year and calculated the estimation of age from the ratio of D-aminoacid and L-aminoacid (D/L ratio) using gaschromatography and the results were below. 1. The aminoacids showed apparent K/L ratio in dentine were aspartic acid, serine. 2. The aspartic acid showed the highest racemic rate and its rate was 0.0012$\pm$0.0003/yr. 3. The relation between the actual age and K/L ratio was very positive correlation(r+0.954) in the estimation of age using aspartic acid. 4. The deviation between the estimated age using D/L ratio of aspartic acid and actual age was $\pm$3.32.

• Applied Biological Chemistry
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• v.28 no.3
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• pp.196-201
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• 1985

Several interesting aromas could be produced from the cultures of Saccharomyces cerevisiae depending on the amino acids used as sole nitrogen source. The yeast produced a fusel oil odor in leucine-medium, an aroma of traditional Korean rice wine in aspartic acid-medium and a floral note in phenylalanine-medium, respectively, Ethanol, iso-amyl alcohol, iso-butanol and n-propanol were found as major volatile con stituents in all the above three cultures. In addition to these compounds, phenethyl alcohol was present as major volatiles both in the aroma concentrates of the phenyl alanine and aspartic acid cultures, and phenethyl acetate only in the phenylalanine culture.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.2
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• pp.163-168
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• 1984

The composition of amino acids and the related compounds of nucleotides in the dorsal muscle of sweet fish Hemibarbus labeo, Mandarin fish Siniperca scherzeri and read fish Gobius similis was analyzed by amino acid autoanalyzer and high performance liquid chromatography. The result showed that IMP was dominant in the nucleotides of all the dorsal muscle of the fishes and a less amount of UMP, hypoxanthine and AMP was detected. In the free amino acid composition, the important amino acids were taurine and histidine in sweet fish, taurine, glycine and histidine in cornet fish, taurine, histidine and alanine in mandarin fish, taurine, proline and threonine in read fish, respectively, and in all the dorsal muscle of fishes, taurine was the dominant amino acid. In the amino acid compositions of the muscle protein, glutamic acid, glycine, aspartic acid and lysine were reached to 44.0% of total amino acids in sweet fish, glutamic acid, aspartic acid, lysine and glycine were 43.5% in cornet fish, glutamic acid, aspartic acid, lysine and leucine were 43.3%, 43.5% of total amino acids in mandarin fish and read fish, respectively. Glutamic acid was the dominant amino acid in all the fresh fishes.