• 대한화학회지
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• 제8권2호
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• pp.85-87
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• 1964

Alloxan에 의한 Amino acids의 spot test에 있어서, alloxan수용액에 lactose를 가해주면, alloxan 자신의 착색을 막을 수 있다. lactose를 포함하는 alloxan수용액은 매우 안정하여서, 실온에서 수 개월 동안 두어도 착색되지 않으며, lactose의 존재로 말미암아, alloxan과 amino acids와의 색반응은 조금도 영향을 받지 않았다. 이시약에 의한 amino acids의 spot test법은 ninhydrin에 의한 spot test보다 예민하고, 또 alloxan 또는 dimethylalloxan을 발색약으로 사용하는 paper chromatography법에 비해, proline (1 ${\gamma}$), hydroxyprolin (5 ${\gamma}$)를 확인할 수 있다는 장점을 가지고 있다.

• Bulletin of the Korean Chemical Society
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• 제27권8호
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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.

• 한국자원식물학회지
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• 제11권3호
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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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• 제7권2호
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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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• 제11권4호
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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.

• 한국작물학회지
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• 제44권3호
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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.

• 대한화학회지
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• 제62권5호
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• pp.364-371
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• 2018

공기가 제거된 0.5 M HCl 과 0.5 M NaCl 용액에서 일어나는 알루미늄의 부식에 대하여 알라닌(Ala), 히스티딘(His) 과 메티오닌(Met)의 부식억제 효과를 조사하였다. HCl에 용해된 Ala, His, Met의 경우 모두 환원반응 속도가 감소되어 부식이 억제 되었으며, 부식억제 효율은 Met$10^{-4\;}M$ 보다 묽은 용액에서 Langmuir 흡착 등온식이 적용되었으나 $10^{-4\;}M$ 보다 진한 용액에서는 흡착된 분자 사이의 상호작용에 의하여 Temkin의 대수함수 등온식이 적용되었다.

• 대한임상검사과학회지
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• 제37권2호
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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.

• 대한화학회지
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• 제35권1호
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• pp.78-84
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• 1991

Enkephalin의 작용을 연장하기 위한 연구이 하나로서 수개의 enkephalin aminopeptidase의 저해물을 합성하였다. 이 펩티드성 저해물은 zinc 결합자리로서 3-amino-2-hydroxy amino acid와 기질양상의 곁사슬을 가진다. 펩티드들은 용액 중에서 DCC/HOBt를 축합시약으로 사용하여 C-말단으로부터 사슬 연장법으로 합성하였다. 합성한 펩티드 저해물들은 모두 enkephalin aminopeptidase에 대하여 강한 저해 작용을 나타내었다.

• 대한화학회지
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• 제37권1호
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• pp.10-21
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• 1993

2-hydroxyethyl methacrylate(HEMA)을 중합한 P(HEMA)막을 통하여 10가지 아미노산들의 확산계수, 분배계수 및 투과도를 용액의 pH 변화하에서 조사 연구하였다. 아미노산의 투과도는 각 아미노산들의 분자형태, 분자크기 및 전하량에 따라 다른 값을 나타냄을 확인하였으며, 특히 용액의 pH에 따라 전하량이 변화하는 각 아미노산은 P(HEMA)막을 통하여 투과시킬 때 모든 아미노산이 중성영역용액에서 가장 많이 투과되고 이때 막은 미세공막으로 작용하며, 염기성영역용액에는 산성영역용액보다 더 많이 투과되고 막은 분배막으로 작용함을 알았다.