• Journal of the Korean Chemical Society
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• v.8 no.2
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• pp.85-87
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• 1964

In order to stabilze alloxan as a reagent for detection of amino acids by spot test, sugars and other reductants were added to the aqueous alloxan solution. It was found that lactose was the best for the purpose. The alloxan reagent containing lactose did not give color change on blank test and was very stable that there was no color change even it was allowed to stand in room temperature for several months. The color reaction with amino acids and some amines was not affected by lactose. This spot test for amino acids is in sensitivity as comparable to that of the previously reported methods and gave color reaction with proline and hydroxyproline to 1${\gamma}$ and 5${\gamma}$ respectively.

• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1194-1198
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• 2006

For the purpose of developing more effective chelating agents, we have synthesized a diethylene triamine pentaacetic acid(DTPA) analogue by using an amino acid. S-(N-Boc-aminophenyl)-Cys(t-Bu4-DTPA) methylester was prepared in 6 steps with total yield of 47.9%. For the sake of introducing a biomolecule to the DTPA derivative, a selective hydrolysis was performed with 3 M HCl/Ethylacetate = 1 : 3 ($25{^{\circ}C}$, 30 min, vigorous stirring). $^{166}Ho$-Cys-DTPA and $^{166}Ho$-Biotin-Cys-DTPA were prepared by mixing $^{166}Ho$ with DTPA derivatives at room temp in a HCl solution (pH = 5) and the radiochemical stabilities (> 99%) were maintained for over 6 hrs in vitro.

• Korean Journal of Plant Resources
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• v.11 no.3
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• pp.272-278
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• 1998

This study was carried out to investigate the functional properties such as nitrogen solubility, emulsifying property , foaming capapcity , water and oil absorption of Camellia (Camellia japonica .) seed protein isolate in condition of distilled water and 0.5M NaCl solution at pH 2.0∼10.0. Nitrogen solubility of Camellia protein isolate in distilled water showed the minimum value at pH 4.0 and increased at pH lower or higher than the isoelectric point(pH 4.0). It was 90.0 %at pH 10.0 Nitrogen solubility of 0.5M NaCl solution showed a similar pattern with that of distrille dwater but was higher than that of distilled water except pH 2.0 and pH 10.0. Emulsifying activity of Camellia seed protein islate showed the minimum value at pH 4.0, but was higher at ether value of pH. Emulsifying stability of protein isolate was stable by heat treatment for 30min, at 80℃ and increased in 0.5M NaCl solution more than that of distille dwater. Foaming capacity of Camellia seed protein isolate in distill3ed water showed the minimum value near the isoelectric point, While it changed little at other values of pH. Foaming stability slowly decreased as, but didn't make a significant difference as time was delayed . Oil absorption was 1.4ml per a sample of 1g and water absorption was 0.9ml per a sample of 1g. The former was higher than the latter . The content of total amino acid of Camellia protein isolate was 43.67% and the major total amino acid of Camellia protein isolate was 43.67% and the major total amino acid was in the order of glutamic acid , arginine, aspartic acid, and leucine.

• Journal of Microbiology and Biotechnology
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• v.7 no.2
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• pp.132-137
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• 1997

A novel protein (HEAAE, High Essential Amino Acid Encoding Protein), rich in essential amino acids ($75{\%}$ of total), was designed and constructed in our laboratory. The designed peptides were analyzed by SYBLE and stable secondary and tertiary structures were predicted. The monomeric form (HEAAE-1) of the protein consists of 20 amino acid residues with four additional amino acids comprising a potential ${\beta}$-turn (HEAAE-4). Size exclusion analysis demonstrated that the monomer is self-aggregates in aqueous solution to form higher ordered multimeric structures, which are very reminiscent of natural plant storage proteins. The DNA encoding this amino acid sequence was synthesized, and from this monomeric gene fragment (heaae-1), the stable tetrameric form of the gene (heaae-4) was generated by subcloning into the E. coli expression vector pKK223-3. A clear 6 kDa polypeptide band corresponding to the molecular weight of the dimeric form (HEAAE-2) was detected. The smeared band which appeared around the molecular weight corresponding to HEAAE-4 of 11 kDa suggested that the tetramer form of this protein might be processed into smaller size products.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.4
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• pp.299-305
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• 2006

Aromatic L-amino acid transaminase is an enzyme that is able to transfer the amino group from L-glutamate to unnatural aromatic ${\alpha}-keto$ acids to generate ${\alpha}-ketoglutarate$ and unnatural aromatic L-amino acids, respectively. Enrichment culture was used to isolate thermophilic Bacillus sp. T30 expressing this enzyme for use in the synthesis of unnatural L-amino acids. The asymmetric syntheses of L-homophenylalanine and L-phenylglycine resulted in conversion yields of >95% and >93% from 150 mM 2-oxo-4-phenylbutyrate and phenylglyoxylate, respectively, using L-glutamate as an amino donor at $60^{\circ}C$. Synthesized L-homophenylalanine and L-phenylglycine were optically pure (>99% enantiomeric excess) and continuously pre-cipitated in the reaction solution due to their low solubility at the given reaction pH. While the solubility of the ${\alpha}-keto$ acid substrates is dependent on temperature, the solubility of the unnatural L-amino acid products is dependent on the reaction pH. As the solubility difference between substrate and product at the given reaction pH is therefore larger at higher temperature, the thermophilic transaminase was successfully used to shift the reaction equilibrium toward rapid product formation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.273-276
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• 1999

Some metabolites and embryo growth of primed tobacco (Nicotiana tabacum L. cv. ‘KFI09’) seeds were observed during priming. The seeds were primed at 15 and $25^{\circ}C$ for 1, 2, 3, 5, 10 and 15 days in a -0.8 MPa polyethylene glycol 6000 (PEG) solution. The time to 50% seed germination (T$_{50}$) was greatly reduced when the seeds were primed at $25^{\circ}C$ when compared with 15$^{\circ}C$. The $\alpha$-amylase activity and sugars and amino acid contents in the seeds primed at $25^{\circ}C$ greatly increased, while $\alpha$-amylase activity was similar, and sugar and amino acid contents increased slightly in the seeds primed at 15$^{\circ}C$. When the seeds were primed at $25^{\circ}C$, growth of the embryo which was enclosed by endosperm was detected, while the endosperm became thinner as the priming duration was extended.d.

• Journal of the Korean Chemical Society
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• v.62 no.5
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• pp.364-371
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• 2018

Inhibition effects of alanine (Ala), histidine (His), methionine (Met) on the corrosion of aluminum were investigated in deaerated 0.5 M HCl and NaCl solution. In HCl solution the inhibition efficiency for the aluminum corrosion depended on the cathodic inhibition, and the inhibition efficiency was increased in the order of Met$10^{-4\;}M$ the adsorption process can be explained by Langmuir isotherm, however, in the case of higher concentration by Temkin logarithmic isotherm due to the interaction between the adsorbed molecules.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.2
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• pp.78-83
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• 2005

The optimum conditions of Cordyceps militaris mycelial growth, purification and characteristics of branched-chain amino acid aminotransferase [BCAT(EC 2.6.1.42)] in this mycelium were studied. Optimum pH, temperature and medium of culture of mycelia were 5.5, $22.5^{\circ}C$ and Hamada medium (HM), respectively. BCAT in homogenate of this mycelia was precipitated by 20-40% saturated solution of ammonium sulfate and then purified by DEAE (diethylaminoethyl)-Sephadex A-50 column chromatography with linear concentration gradient and Sephadex G-200 gel filtration. A single band of purified enzyme was detected on SDS-PAGE (sodium dodecylsulfate-polyacrylamide gel electrophoresis). Optimum pH and temperature of BCAT were found to be 7.8 and $29^{\circ}C$, respectively. It showed activity toward L-leucine, L-isoleucine and L-valine as a substrate. The Km values of this enzyme for L-leucine were determined to be 5.88 mM for L-leucine.

• Journal of the Korean Chemical Society
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• v.35 no.1
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• pp.78-84
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• 1991

In an effort to increase effective action of enkephalins, several peptide inhibitors of enkephalin aminopeptidase have been synthesized. The peptides contain 3-amino-2-hydroxy amino acid as a zinc binding site and side chains of substrate pattern. The peptides were synthesized in solution by chain elongation from C-terminal end using DCC/HOBt as coupling reagent. The peptides are shown to have very strong inhibitory activity against enkephalin aminopeptidase.

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.10-21
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• 1993

The transport phenomena of ten amino acid molecules through poly(2-hydroxyethyl methacrylate), P(HEMA) membrane have been investigated in various range pH solutions. It is found that the permeability and diffusivity of the amino acids through membrane depended on the different shape, size and the charge of them are changed by the pH. The permeabilities and diffusivities of amino acids have the largest value in the neutral solution. In this case, they are diffused through free water in the P(HEMA) membrane and the diffusion mechanism is the pore type. The basic solution have larger value than the acidic it. Whether the diffusion mechanism of the core type or the partition type, it is depended on the effect of side chain of the amino acid in basic and acidic solution.