• YAKHAK HOEJI
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• v.40 no.4
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• pp.422-427
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• 1996

The anti-Ex-A IgG was specifically labeled with stable isotopes, DL-His-2,4-$d_2$, L-Phe-$d_5$, L-Trp-$d_5$, L-Tyr-2,6-$d_2$ and L-[1-$^{13}C$]Trp, by growing hybridoma cell in serum-free medium. By use of NMR spectroscopy with selectively labeled Fab fragment, we applied a paratope mapping on antigen-antibody complex. Assignments of the observed carbonyl carbon resonances have been determined by using $^{13}C$-$^{15}N$ double labeling method in order to assign the Trp resonances. Photo CIDNP was also applied to investigate the antigen-binding site(s) on the surface residues of antibody. We found that Trp 36, which is located at the $V_H$ domain, is an important residue to bind to Ex-A, however, two Tyr on the surface of anti-Ex-A IgG plays no crucial role to bind to antigen. On the basis of these results, we demonstrate that stable isotope-aided NMR strategy can be extended to molecular structural analyses of the complex of an Fab fragment and a protein antigen.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.2
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• pp.337-342
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• 2009

Acquired pigmentary skin diseases such as abnormal melanogenesis, vitiligo, chloasma and inflammatory pigmentation are related to regulate the melanin production, In this study, an ethanol extract of Hovenia dulcis Thunb.(EHD) makedly inhibited melanin biosynthesis and suppressed, the protein expression of tyrosinase, tyrosinase-related protein 1(TRP-1), and tyrosinase-related protein 2(TRP-2) in B16F10 cells. On the other hand, EHD did not inhibit mushroom tyrosinase activity. These results indicate that EHD may contribute to the inhibition of melanin biosynthesis through regulating tyrosinase activity and expression, and serve as a new candidate in the design of new skin-whitening or therapeutic agents.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.2
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• pp.236-241
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• 2010

The purpose of this study was to investigate the mechanism of ethanol extract of Agrimonia pilosa Ledeb. (EAP)-reduced melanogenesis and diphenyl-picryl-hydrazyl (DPPH) radical scavenging activity. Agrimonia pilosa Ledeb., a perennial herbaceous plant, has been used as an antihemorrhagic, anthelminntic, and antiinflammatory agents in Chinese herbal medicine. In the present study, we observed that melanin synthesis and tyrosinase activity of B16F10 cells were significantly decreased by EAP. However, EAP could not suppress tyrosinase activity in the cell-free system, whereas kojic acid directly inhibited tyrosinase activity. Furthermore, EAP decreased the protein expression of tyrosinase, tyrosinase-related prootein 1 (TRP-1), and tyrosinase-related prootein 2 (TRP-2). EAP scavenged DPPH radical up to 41% with 100 ${\mu}g/m{\ell}$ concentration. These results suggest that the hypopigmentary effect of EPA was due to regulation of tyrosinase protein.

• Interdisciplinary Bio Central
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• v.5 no.3
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• pp.6.1-6.7
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• 2013

Many insects such as mosquitoes cause life-threatening diseases such as malaria, yellow fever and West Nile virus. Malaria alone infects 500 million people annually and causes 1-3 million death per year. Volatile insect repellents, which are detected through the sense of smell, have long been used to protect humans against insect pests. Antifeed-ants are non-volatile aversive compounds that are detected through the sense of taste and prevent insects from feeding on plants. The molecular targets and signaling path-ways required for sensing insect repellents and antifeedants are poorly understood. Transient Receptor Potential (TRP) Ca2+-permeable cation channels exist in organisms ranging from C. elegans to D. melanogaster and Homo sapiens. Drosophila has 13 family members, which mainly function in sensory physiology such as vision, thermotaxis and chemotaxis. G protein-coupled receptors (GPCRs) initiate olfactory signaling cascades in mammals and in nematodes C.elegans. However, the mechanisms of G protein signaling cascades in insect chemosensation are controversial. In this review, I will discuss the putative roles of G protein-coupled receptors (GPCRs) and Transient Receptor Potential (TRP) channels as targets for insect repellents.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.517.2-517
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• 1986

The regulation of 3 ammonia assimilatory enzymes GDH(glutamate dehydrogenase), GS(glutamine synthetase) and GOGAT (glutamate synthase), have been examined in C. glutamicum for the biosynthesis of glutamate and glutmine. The cell free extracts of 3 kinds of arg, his and trp auxotrophs were investigated the activities of -ketoglutarate dehydrogenase, GDH, GS, and GOGAT on the media cultured with nitrogen excess and limiting conditions. Trp and his howed higher level of glutamate and glutamine than that of parental strain. The inhibition of GS activities by ADP suggested that GS is regulated by energy charge in C. glutamicum. The results with his, trp, glyc, ala, ser, and GMP implied that a system of feedback inhibition were effective. Three enzyme biosynthesis is repressed by nitrogen sources such as trp, pro, glyc, ala, ser and tyrosine.

• Journal of Life Science
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• v.27 no.4
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• pp.423-429
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• 2017

Hair color is determined by kind and amount of melanin. Melanocyte mainly synthesizes melanin from L-tyrosine by stimulation of ultra violet. Reactive oxygen species (ROS) play an important role in greying hair. Polygonum multiflorum radix has been reported to inhibit the aging process that black color of hair is turned into grey color. The aim of this study is to investigate the effect of Polygoni multiflorium radix ethanol extract (PMEE) on melanin synthesis related to black hair growth. In anti-oxidant experiment, PMEE decreased DPPH radical and increased reducing power, indicating that PMEE could eliminate ROS involved in greying hair. PMEE decreased cell viability in a dose-dependent manner. Furthermore, the effect of PMEE on the production of melanin was determined by DOPA assay and tyrosinase activity. PMEE increased tyrosinase activity and promoted melanin synthesis. In addition, the expression levels of tyrosinase, tyrosinase related protein-1 (TRP-1), tyrosinase related protein-2 (TRP-2) and microphthalmia-associated transcription factor (MITF), as well as anti-oxidant enzymes such as superoxide dismutase (SOD-3) and catalase were examined using western blot analysis. The expression levels of SOD-3 and catalase were decreased due to the enhanced antioxidant activity of PMEE. In particular, PMEE increased the expression levels of tyrosinase and TRP-2. These results suggest that PMEE could promote melanin synthesis that involved in tuning gray hair into black hair.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.119-124
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• 1988

The desmutagenic effects of ${\alpha}$-hydroxycarbonyl compounds, such as glyceraldehyde, glycolaldehyde, dihydroxyacetone, furfural, 5-hydroxymethylfurfural, maltol, acetol and acetoin and ${\alpha}$-dicarbonyls, such as diacetyl, glyoxal, methyl glyoxal and 2, 3-pentanedione were investigated against the mutagenic heterocyclic amines, such as Trp-P-1, Trp-P-2, Glu-P-1, Glu-P-2 and IQ. Most of the carbonyl compounds suppressed the mutagenicity of heterocyclic amines for S. typhimurium TA98, ${\alpha}$-dicarbonyl compounds showing a higher desmutagenic effect than ${\alpha}$-hydroxycarbonyl compounds. Among the ${\alpha}$-hydroxycarbonyl compounds, glyceraldehyde, glycolaldehyde and dihy-droxyacetone showed more effective desmutagenicity, and diacetyl among the ${\alpha}$-dicabonyl compounds had the highest desmutagenic effect. These carbonyl compounds alone also showed mutagenicity to S. typhimurium TA100 without S-9 mix. The reaction of carbonyl compounds with mutagenic heterocyclic amines also eliminated the mutagenicity of the former for S. typhimurium TA100.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.4
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• pp.265-270
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• 2009

To develop a natural stimulating agent for hair melanogenesis, we investigated the stimulatory effects of Epimedium koreanum Nakai extract (EKNE) on melanogenesis. EKNE both increased melanin content in B16 melanoma cells up to about 104 % and intracellular tyrosinase activity up to about 95 % at a concentration of $50\;{\mu}g/mL$ without cell cytotoxicity (below $100\;{\mu}g/mL$). From the result of western blot, we could find that EKNE dose-dependently induce the expression of TRP-2. Also, EKNE increased melanogenesis up to about 25 % at a concentration of 5 % (w/v) in back hair of C3H/Hej mouse. These results suggest that EKNE has an effect to stimulate melanin formation through the induction of tyrosinase activity and TRP-2 expression which are involved in melanin synthesis in melanocyte. Therefore, we suggest that EKNE could be used as a useful melanogenesis stimulator for development of natural hair cosmetics.

• The Journal of Korean Obstetrics and Gynecology
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• v.22 no.4
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• pp.28-45
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• 2009

Purpose: This study was performed to elucidate the inhibitory effect of Yukmijihwangtanghapyijihwangagambang (YM) on melanin synthesis in B16F10 melanoma cells. Methods: To demonstrate the inhibitory effects of YM on melanin synthesis, we measured the amount of released and produced melanin in B16F10 melanoma call. Also, we evaluated tyrosinase-activity in vitro as well as in B16F10 melanoma call. And to investigate the action mechanism, we assessed the gene expression of tyrosinase, TRP-1, TRP-2, PKA, $PKC{\beta}$, ERK-1 ERK-2, AKT-1 and MITF in B16F10 melanoma call. Results: 1. YM decreased the release and production of melanin in B16F10 melanoma cells. 2. YM decreased tyrosinase activity in vitro and in B16F10 melanoma cells. 3. YM decreased the expression of tyrosinase, TRP-1, TRP-2 in B16F10 melanoma cells. 4. YM decreased the expression of PKA, $PKC{\beta}$ in B16F10 melanoma cells. 5. YM increased the expression of ERK-1, ERK-2 and AKT-1 in B16F10 melanoma cells. 6. YM decreased the expression of MITF in B16F10 melanoma cells. Conclusion: From these results, it may be concluded that YM has antimelanogenetic effects.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.2
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• pp.45-57
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• 1999

Melanocytes, derived from neural crest, make melanin and protect skin from the hazardous ultraviolet light. Melanocytes with dendritic process has similar morphology with neurogenic cells and share growth factor receptors such as neurotrophin receptors. Melanogenesis can be regulated by ultraviolet light and inflammation of the skin. In addition, several factors such as hormone, cytokines, arachidonic acid can affect the proliferation and melanogenesis of melanocytes. For melanogenesis, melanocytes need expression of various genes including tyrosinase, TRP-1, TRP-2. In addition, melanin need to be transferred from melanocytes to surrounding keratinocytes. The biology of melanocytes is complex and mechanism of melanocytes proliferation and melanogenesis is still under the investigation.