• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.467-472
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• 2003

Optically pure α-mono- and α, α-disubstituted β-amino acids were conveniently prepared in four steps and in 27-40% overall yields from the correspondingly substituted racemic β-hydroxy acids that can be readily obtained from diethyl malonate. In the synthesis, (S)-phenylethylamine has been used as a resolving agent and as a source of the amino group in the β-amino acids.

• Microbiology and Biotechnology Letters
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• v.22 no.6
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• pp.636-642
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• 1994

Essential amino acids involving in the catalytic mechanism of the $\beta$-D-xylosidase of Bacillus stearothermophilus were determined by chemical modification studies. Among various che- mical modifiers tested N-bromosuccinimide (NBS), $\rho$-hydroxymercurybenzoate (PHMB), N-ethylma- leimide, 1-[3-(di-ethylamino)-propyl]$-3-ethylcarbodi-imide (EDC), and Woodward's Reagent K(WRK)inactivated the enzyme, resulting in the residual activity of less than 20%. WRK reduced the enzyme activity by modifying carboxylic amino acids, and the inactivation reacion proceeded in the form of pseudo-first-order kinetics. The double-lagarithmic plot of the observed pseudo-first- order rate constant against the modifier concentration yielded a reaction order of 2, indicating that two carboxylic amino acids were essential for the enzyme activity. The $\beta$-D-xylosidase was also inactivated by N-ethylmaleimide which specifically modified a cysteine residue with a reaction order of 1, implying that one cysteine residue was important for the enzyme activity. Xylobiose protected the enzyme against inactivation by WRK and N-ethylmaleimide, revealing that carboxylic amino acids and a cysteine residue were present at the substrate-binding site of the enzyme molecule.

• Proceeding of EDISON Challenge
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• 2014.03a
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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.

• Fisheries and Aquatic Sciences
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• v.4 no.4
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• pp.192-196
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• 2001

Proopiomelanocortin (POMC) plays an essential role in the disease resistance system and is the precursor protein of biologically active peptides such as adrenocorticotropin (ACTH), $\alpha-melanocyte-stimulating$ hormone $(\alpha- MSH)$, $(\beta-melanocyte-stimulation hormone\;(\beta- MSH)$ and $\beta-endorphin$. We have isolated and sequenced two different forms of POMC cDNA, POMC-I and POMC-II, from a pituitary cDNA library of flounder. POMC-I cDNA consisted of 956 bp corresponding to deduced amino acids of 216 residues and POMC-II cDNA was 982 bp in length corresponding to 194 amino acids, respectively. The results of deduced amino acids analysis of the clones showed high sequence homology with previously reported POMCs amino acid sequences from various species. The homology between flounder POMC-I and -II is$57\%$ identity. We also constructed a phylogenetic tree based on POMC amino acid sequences.

• Journal of Sericultural and Entomological Science
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• v.41 no.3
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• pp.147-153
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• 1999

Chitinolytic enzymes such as ${\beta}$-N-acetylglucosaminidase are major hydrolases involved in insect molting. We have isolated, sequenced a CDNA encoding ${\beta}$-N-acetylglucosaminidase from the silkworm, Bombyx mandarina, and compared its sequence with genes encoding chitinolytic enyzmes from other sources. The insert DNA in the clone is 3,284 nucleotides long with an open reading frame of 1,788 nucleotides that encodes a protein of 596 amino acids with a molecular weight of 68.2 kDa. There is a 3’-untranslated region composed with 1.479 nucleotides and are several potential polyadenylation signals. The predicted amino acid sequence apparently contains a leader peptide of 23 amino acids. A search of the amino acids sequence databases for sequences similarities to other ${\beta}$-N-acetylglucosaminidases or ${\beta}$-N-acetylhexosaminidases. The highest similarity matched with the enzyme from B. mori, which has a sequence identity of 95%. On the other hand, the identity between the B. mandarina enzyme and those from M. sexta and human are 70% and 24%, respectively.

• Culinary science and hospitality research
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• v.22 no.6
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• pp.71-77
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• 2016

To determine the nutritional value of domestic tomatoes, the levels of amino acids, amino acid metabolites, and the bioactive compound ${\gamma}-aminobutyric-acid$ (GABA) were analyzed in three domestic tomato varieties (Rafito, Momotaro, and Medison). Eighteen free amino acids were found, and total free amino acid content was 3,810.21~4,594.56 mg/100 g (dry weight). L-glutamic acid (L-Glu) was the most abundant amino acid, ranging from 1,866.60 mg/100 g for Momotaro to 2,417.45 mg/100 g for Medison. The next most abundant amino acids were L-glutamine (L-Gln) and L-aspartic acid (L-Asp). The three tomato varieties had a good balance of all the essential amino acids except tryptophan. Total essential amino acid content was 274.26~472.71 mg/100 g (dry weight). The following amino acid metabolites were found: L-carnitine (L-Car), hydroxylysine (Hyl), o-phosphoethanolamine (o-Pea), phosphoserine (p-Ser), ${\beta}-alanine$ (${\beta}-Ala$), N-methyl-histidine (Me-His), ethanolamine (EtNH2),and L-citrulline(L-Cit). Large quantities of GABA were found in all three varieties: 666.95-868.48 mg/100g (dry weight). These results support the use of these tomato varieties as nutritious food materials.

• Journal of Microbiology
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• v.35 no.4
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• pp.341-346
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• 1997

In order to express recombinant porcine TGF-${\beta}1$ protein in a baculovirus expression system the entire TGF-${\beta}1$gene containing extra amino acids at the N terminus was cloned into pFBa and pFBb of the Bac-To-$Bac^{TM}$ baculovirus expression system. One of the clones contained 106 extra amino acids and was designated pFBa-106 TGF-${\beta}1$, and the other had 28 extra amino acids and was designated pFBb-28 TGF-${\beta}1$. The orientation of the gene was identified with restriction enzyme mapping and PCR with internal TGF-${\beta}1$ primers. Sf-9 cells were infected at a m.o.i. of 10 by the recombinant viruses generated from the two expected sizes of 55 kD and 46.4kD. these precursor forms of TGF-${\beta}1$ with a polyclonal antibody against human TGF-${\beta}1$. No mature form of TGF-${\beta}1$ protein was detected on SDS gels and an immunoblot indicated that TGF-${\beta}1$ precursor is not properlu processed in insect cells.

• Journal of Life Science
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• v.11 no.2
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• pp.92-93
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• 2001

Bacillus sp. KYJ 963, which was isolated from Korean salt-fermented anchovy (anchovy-jeot), produces an extracellular ${\beta}$-amylase. The analysis of the digestion products of substrates by thin layer chromatography from the purified protein revealed that the enzyme could not hydrolyze maltose or ${\alpha}$-cyclodextrin. In the amino acid composition analysis, the major characteristic of the ${\beta}$-amylase was the high proportion of amino acids that possess short side chain such as glycine and alanine.

• Archives of Pharmacal Research
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• v.2 no.2
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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.

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1775-1779
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• 2006

A liquid chromatographic chiral stationary phase (CSP) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxilic acid without extra free aminopropyl groups on silica surface has been demonstrated to be quite effective for the resolution of various $\beta$-amino acids. The retention factors ($k_1$) for the resolution of $\beta$-amino acids on the CSP were quite large and the large retention factors might be quite attractive along with the reasonable separation factors ($\alpha$) for preparative scale enantioselective chromatography. The large retention factors on the CSP were found to be reduced effectively by adding ammonium ion to mobile phase without sacrificing the chiral recognition efficiency of the CSP. Consequently, the CSP is also quite applicable for use in analytical enantioselective chromatography.