• Food Science of Animal Resources
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• v.32 no.6
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• pp.796-802
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• 2012

This study was conducted in order to investigate the effect of different drying methods on free amino acids and dipeptide contents, Warner-Bratzler shear force and sensory property of beef jerky products. The drying methods used for this study were sun-drying, shade-drying and hot air-drying methods. The sun-dried beef jerky had the highest free amino acids (277.45 mg/100 g) followed by shade-dried (206.43 mg/100 g) and hot air-dried (111.88 mg/100 g) ones, whereas the amount of dipeptides were the highest in the shade-dried beef jerky followed by sun-dried and hot air-dried ones. The fatty acid composition of the beef jerky was not shown any difference among the beef jerkies with 3 different drying methods. The color $L^*$-value of the beef jerky was lower in the hot-air dried, while the $a^*$-value was higher in the sun-dried one. The shade-dried jerky showed a lower $b^*$-value. The shear force of beef jerky was lower when it was either sun-dried or shade-dried than when it was hot air-dried. Sensory evaluation revealed that hot air-dried beef jerky scored lower than the sun-dried and shade-dried ones (p<0.05). Therefore, using either the sun drying or shade drying methods is more desirable than using the hot air drying method when manufacturing beef jerky for superior physicochemical qualities.

• Bulletin of the Korean Chemical Society
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• v.17 no.4
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• pp.401-404
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• 1996

• Bulletin of the Korean Chemical Society
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• v.18 no.5
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• pp.461-462
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• 1997

• Bulletin of the Korean Chemical Society
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• v.18 no.3
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• pp.261-262
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• 1997

• Journal of the Korean Magnetic Resonance Society
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• v.1 no.2
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• pp.71-78
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• 1997

The magnetic anisotropy effects of peptide group in structured protein on proton chemical shift have been investigated using trialanine modeling. The structure dependent part of chemical shift of C${\alpha}$H of the second amino acid residue was assumed to come purely from the magnetic anisotropy effects of C=O and C-N bonds of peptide in the direct neighborhood and thus to be dependent on and $\psi$ angle of this dipeptide. A set of dipeptide models with different and $\psi$angles were generated and from these models the chemical shift values were calculated using known algorithm to emphasize the role of parameters used in the equation. Comparison of sets of different parameters resulted in an optimized parameters which could reproduce the statistical chemical shift values observed in proteins with respect ot the secondary conformation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.220-220
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• 1994

출발물질로 L-tyrosine을 사용하여 요오드화, 에스테르화, N-BOC 및 0-Bn보호기화 및 N 탈보호기화를 행하여 5단계에 걸쳐 41%의 수율로 methyl 0-Bn-3-iodotyrosinate를 합성하였다. 또한 Ullmann coupling의 반응성 향상을 위해 5위치에 nilro기가 도입된 methyl 0-Bn-3-iodo-5-nitrotyrosinate를 좋은 수율로 합성하였다. 이들에 N-BOC-tyrosine을 결합시켜 대응하는 dipeptide를44% 및 39%의 수율로 각각 얻었다. 일단 dipeptide에 대해 Ullmann coupling을 행하였으나 원하는 cyclic product는 얻을수 없었다. 전년도에 이어 methyl N-BOC-0-Bn-3-hydroxytyrosinate를 합성하였다. 이로 부터 4-iodobenzaldehyde에 Ullmann coupling을 행하여 원하는 페놀성 biaryl ether를 합성하고자 하였다. 또한 $\beta$-hydroxyhomoserine의 합성을 위해 출발물질로 cis-1,4-buterdiol을 사용하여 12단계의 합성반응을 행하여 좋은수율로 원하는 화합물을 합성하였다.

• Journal of Microbiology and Biotechnology
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• v.5 no.6
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• pp.319-323
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• 1995

A chromogenic mimic of phenlyalanyl-dipeptide, L-phenylalanyl-L-2-sulfanilylglycine (PSG), was synthesized and examined for its usability in leucine aminopeptidase (LAP) assay. The enzyme activity was easily determined by measuring the amount of diazotized adduct of sulfanilic acid released upon hydrolysis of PSG ($\varepsilon^{420}$=18,000/M/cm). Under the experimental conditions employed, PSG showed a Km of 0.063 mM and a Kcat of 1683/min, assessable less than 0.1 $\mu$ g of LAP per milliliter. And the presence of aminopeptidase M (APM) was suggested to be negligible in LAP assay. This novel assay can circumvent the occasional yellow background in biological systems, i.e., serums, etc..

• Bulletin of the Korean Chemical Society
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• v.12 no.4
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• pp.376-379
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• 1991

Pyrazolone group containing resin was tested as an acyl carrier in solid phase peptide synthesis. Several kinds of dipeptide derivatives were prepared by aminolysis reactions of Boc-amino acid-pyrazolone resin active ester with various carboxyl protected amino acid derivatives. It was found that the rates of aminolysis reactions were largely dependent on the bulkiness of the amino acid side chains, the carboxyl protecting groups, and the swelling property of the resin. All the dipeptide derivatives were obtained in high yield in 20-30 minutes, and the pyrazolone resin could be reused repeatedly in peptide synthesis without any change of its reactivity.

• Fisheries and Aquatic Sciences
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• v.17 no.4
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• pp.433-439
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• 2014

We compared the utilization efficiency of free lysine (FL) and dipeptide lysine-glycine (LG) in terms of growth performance and whole-body amino acid composition in olive flounder Paralichthys olivaceus. A basal experimental diet was formulated to contain 0.5% (basal) lysine from fish meal, and four other diets were prepared by supplementing 0.5% or 1.0% of either FL or LG. The experiment was performed in triplicate, and 20 randomly selected fish averaging $5.41{\pm}0.16g$ were fed one of the test diets at the rate of 3% BW/day twice daily for 6 weeks. At the end of the feeding trial, fish fed the basal diet showed significantly less weight gain than did the other groups. The results of a two-way ANOVA showed that both lysine level (P = 0.001) and type (P = 0.034) influenced growth rate; however, we found no significant interaction between lysine level and form (P > 0.05). Our results revealed a significant improvement in protein efficiency ratio (PER) with each increment of dietary lysine, and the groups fed LG-supplemented diets showed higher PER than did those offered FL. Hepatosomatic and viscerosomatic indices were significantly influenced by lysine level and form, and higher values were recorded in fish fed diets containing LG. Significantly higher whole-body arginine levels were found in LG-fed groups, and a significant interaction was observed between lysine level and form (P = 0.009). Whole-body valine and aspartic acid contents were affected by lysine level, and alanine concentration was influenced by both lysine level and form. Our findings indicate that juvenile olive flounder can utilize LG more efficiently than FL for protein synthesis.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3017-3021
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• 2013

Coumaroyl dipeptide amide, Coumaric acid-LG-$NH_2$, was prepared successfully using the solid-phase method, and its efficacy as a skin whitening agent was studied. Coumaric acid-LG-$NH_2$ was prepared with Rink-amide resin, and 96.354% of purity was obtained. Using MTT assay and LDH release assay, we found that it exhibited very low cytotoxicity. And, we found that Coumaric acid-LG-$NH_2$ inhibited tyrosinase activity dose-dependently and showed superior tyrosinase inhibitory activity to well-known whitening agent, arbutin. $IC_{50}$ value of Coumaric acid-LG-$NH_2$ was 182.4 ${\mu}M$, and $IC_{50}$ value of arbutin was 384.6 ${\mu}M$. Also, in measurement of melanin contents using B16F1 melanoma cell lines, Coumaric acid-LG-$NH_2$ reduced melanin production induced by ${\alpha}$-MSH statistically significant, and showed superior melanin inhibitory activity to p-coumaric acid or arbutin. In addition, Coumaric acid-LG-$NH_2$ reduced MC1R mRNA expression level. Thus, we concluded that MC1R pathway is the significant pathway of Coumaric acid-LG-$NH_2$, and Coumaric acid-LG-$NH_2$ has great potential to be used as novel whitening agents.