• Journal of Applied Biological Chemistry
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• 제54권1호
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• pp.56-62
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• 2011

Tyrosinase 저해활성화 반응에 대한 polyhydroxy 치환된 flavone 유도체(1-25) 중, hydroxyl-치환기($R_1-R_9$)들의 역할을 이해하기 위하여 Free-Wilson 분석과 tyrosinase (PDB ID: Deoxyform (2ZMX) 및 Oxy-form; 1WX2)의 활성화 지점에 대한 분자도킹이 연구되었다. Free-Wilson 분석으로부터 $R_1-R_9$ 치환기중에서 $R_1$=hydroxyl 치환기가 tyrosinase 저해활성에 가장 큰 영향을 미치고 있음을 알았다. 기질분자의 hydroxyl 치환기들과 tyrosinase의 반응점 내 아미노산 잔기들 사이의 수소결합들은 안정한 기질-수용체 착 화합물을 형성하는데 기여하였다. 특히, 수소결합성에 기초한 비경쟁적 저해활성화 반응은 기질분자의 hydroxyl 치환기들과 tyrosinase의 반응점 내 peroxide 산소원자(Per404) 사이의 수소결합을 경유하여 일어날 것임을 제안하였다.

• 한방안이비인후피부과학회지
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• 제22권2호
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• pp.104-117
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• 2009

Objective : Melanin is one of the most important facor in skin color. Melanin protects human skin from ultraviolet radiation otherwise it causes melanin pigmentation. So this experiment is carried out for test whether Scutellaria baicalensis Georgi(SBG) inhibits melanin synthesis and tyrosinase activity in mouse B16 melanoma cells. Method : The melanin synthesis inhibition effects of SBG were examined by in vitro melanin production assay. We assessed inhibitory effects of SBG on melanin contents from B16F1 melanoma cell, on tyrosinase activity(cell and cell free system), effect of SBG on the expression tyrosinase, Microphthalmia-associated Transcription Factor(MITF), Extracellular signal-regulated Kinase(ERK). Result : SBG inhibited melanin synthesis induced $\alpha$-MSH($\alpha$-Melanin Stimulating Hormone) in B16F1. SBG inhibited tyrosinase activity and expression. And SBG down-regulates MITF and stimulated ERK activation in B16F1. Conclusion : According to above results, SBG was improved its suppression effect to the inhibition of melanin synthesis, tyrosinase activation, and tyrosinase promotor activation. So SBG is considered to be used for an strong source of skin whitening effect.

• 생명과학회지
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• 제17권6호통권86호
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• pp.873-875
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• 2007

Effects of hot-water extract from Sasa quelpaertensis leaf (HWES) on melanogenesis were investigated in B16/F10 mouse melanoma cells. HWES inhibited cellular tyrosinase activity and melanin biosynthesis in a dose-dependent manner. Western blotting analysis showed that HWES dose-dependently inhibited tyrosinase and tyrosinase related protein-1 expression. Also, HWES suppressed sustained ERK activation in a concentration-dependent manner, suggesting that HWES inhibits the melanin biosynthesis through the suppressive effect against pathway involving sustained ERK activation.

• Journal of Applied Biological Chemistry
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• 제64권4호
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• pp.323-331
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• 2021

Lincomycin is a lincosamide antibiotic isolated from the actinomycete Streptomyces lincolnensis. Moreover, it has been found to be effective against infections caused by Staphylococcus, Streptococcus, and Bacteroides fragillis. To identify the melanin-inducing properties of lincomycin, we used B16F10 melanoma cells in this study. The melanin content and intracellular tyrosinase activity in the cells were increased by lincomycin, without any cytotoxicity. Western blot analysis indicated that the protein expressions of tyrosinase, tyrosinase related protein 1 (TRP1) and TRP2 increased after lincomycin treatment. In addition, lincomycin enhanced the expression of master transcription regulator of melanogenesis, a microphthalmia-associated transcription factor (MITF). Lincomycin also increased the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and decreased the AKT phosphorylation. Moreover, the activation of tyrosinase activity by lincomycin was inhibited by the treatment with SB203580, which is p38 inhibitor. Furthermore, we also found that lincomycin-induced tyrosinase expression was reduced by H-89, a specific protein kinase A (PKA) inhibitor. These results indicate that lincomycin stimulate melanogenesis via MITF activation via p38 MAPK, AKT, and PKA signal pathways. Thus, lincomycin can potentially be used for treatment of hypopigmentation disorders.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 추계학술대회
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• pp.95-95
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• 2018

In this study, we investigated the effect of branch extracts from Vaccinium oldhamii (VOB) on melanin synthesis in B16F10 cells. VOB promoted melanin production in absence or presence of ${\alpha}$-melanocyte-stimulating hormone (${\alpha}-MSH$) in B16F10 cells. However, VOB did not affect the expression of tyrosinase and TRP-1 associated with melanin synthesis at the mRNA and protein level in B16F10. But, VOB decreased TRP-2 protein level and induced tyrosinase activation in B16F10 cells. Inhibition of tyrosinase activity and tyrosinase knockdown attenuated VOB-mediated melanin synthesis. In conclusion, it is thought that VOB may stimulate melanin synthesis through activating tyrosinase activity.

• Bulletin of the Korean Chemical Society
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• 제28권5호
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• pp.758-762
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• 2007

A new alkyldithiocarbonate (xanthate), as sodium salts, C2H5OCS2Na, was synthesized by the reaction between CS2 with ethyl alcohol in the presence of NaOH. The new xanthate was characterized by 1H NMR, IR and elemental analysis. Then, the new synthesized compound was examined for functional study of cresolase activity of Mushroom Tyrosinase (MT) from a commercial source of Agricus bisporus in 10 mM phosphate buffer pH 6.8, at three temperatures of 10, 20 and 33℃ using UV spectrophotemetry. 4-[(4-methylphenyl)- azo]-phenol (MePAPh) was used as a synthetic substrate for the enzyme for cresolase reaction. The results show that ethyl xanthate can activate or inhibit the cresolase activity of mushroom tyrosinase depending to the concentration of ethyl xanthate. It was concluded that the enzyme has two distinct sites for ethyl xanthate. The first one is a high-affinity activation site and the other is a low-affinity inhibition site. Activation of the enzyme in the low concentration of ethyl xanthate arises from increasing the affinity of binding for the substrate as well as increasing the enzyme catalytic constant. The affinity of ligand binding in the activation site is decreased by increasing of the temperature, which is the opposite result for the inhibition site. Hence, the nature of the interaction of ethyl xanthate is different in two distinct sites. The binding process for cresolase inhibition is only entropy driven, meanwhile the binding process for cresolase activation is not only entropy driven but also enthalpy driven means that hydrophobic interaction is more important in the inhibition site.

• 한국자원식물학회지
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• 제35권6호
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• pp.704-712
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• 2022

Research on whitening materials using natural alternatives is actively being conducted. The aim of this study was to investigate the in vitro inhibitory effects of Ranunculus chinensis Bunge (RCB) on melanogenesis and associated enzymes, such as tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 in B16F10 murine melanoma cells. We found that RCB extract significantly attenuated melanin synthesis and reduced the activity of intracellular tyrosinase, a rate-limiting melanogenic enzyme. Western blot analysis showed that RCB extract decreased the protein expression of tyrosinase and TRP-1. In addition, it significantly decreased the expression of microphthalmia-associated transcription factor (MITF), a key regulator of melanogenesis. Extracellular signal-regulated kinase (ERK) activation has been reported to be involved in the inhibition of melanogenesis. Thus, we investigated whether the hypopigmentary effects of RCB extract were related to the activation of ERK. RCB extract induced ERK phosphorylation in a dose-dependent manner. Furthermore, it markedly inhibited body pigmentation in a zebrafish model. Our results suggest that RCB extract inhibits melanogenesis by activating ERK pathway-mediated suppression of MITF and its downstream target genes, including tyrosinase. Therefore, RCB extract can be used as a whitening agent in the development of functional cosmetics.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1500-1506
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• 2011

Tyrosinase is a widespread enzyme with great promising capabilities. The Lineweaver-Burk plots of the catecholase reactions showed that the kinetics of mushroom tyrosinase (MT), activated by $Co^{2+}$ and $Zn^{2+}$ at different pHs (6, 7, 8 and 9) obeyed the non-essential activation mode. The binding of metal ions to the enzyme increases the maximum velocity of the enzyme due to an increase in the enzyme catalytic constant ($k_{cat}$). From the kinetic analysis, dissociation constants of the activator from the enzyme-metal ion complex ($K_a$) were obtained as $5{\times}10^4M^{-1}$ and $8.33{\times}10^3M^{-1}$ for $Co^{2+}$ and $Zn^{2+}$ at pH 9 and 6 respectively. The structural analysis of MT through circular dichroism (CD) and intensive fluorescence spectra revealed that the conformational stability of the enzyme in these pHs reaches its maximum value in the presence of each of the two metal ions.

• KSBB Journal
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• 제19권2호
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• pp.118-124
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• 2004

본 연구에서는 효모에서 분리한 melanoston이라고 명명된 멜라닌 생성을 억제하는 물질의 작용 기전을 밝히기 위한 것이다. $\alpha$-MSH를 처리한 B16 melanoma 세포에서 melanoston은 tyrosinase mRNA 발현양을 10% 정도 저해되는데 그쳤으며 western blotting을 이용한 단백질 측정에서도 이와 비슷한 정도의 단백질 생성 억제를 보였다. 그러나 B16 세포 배양액에 melanoston을 첨가할 경우 세포내 tyrosinase 활성이 33% 까지 감소되는 것으로 나타나 metanoston이 tyrosinase inhibitor는 아니지만 세포내 tyrosinase 활성화 (activation) 과정을 억제하는 것으로 추측할 수 있었다. 또한 광학 현미경을 이용한 morphology 관찰에서 $\alpha$-MSH를 처리한 세포에서는 많은 dentrite가 형성되면서 세포분화가 일어나는 반면 melanoston를 처리한 경우에는 dendrite가 감소하면서 세포형태가 대조군과 비슷하게 회복 되는 것을 알 수 있었다. 또 FITC-anti-tyrosinase-Ab를 이용한 형광 염색을 통해서는 $\alpha$-MSH만 처리한 세포에서는 tyrosinase의 분포가 dendrite를 포함한 세포 전체로 퍼져나가는 것을 관찰할 수 있었고 $\alpha$-MSH와 melanoston을 동시에 처리한 세포에서는 대조군과 비슷하게 tyrosinase가 핵 주변에서만 관찰되어 melanoston이 B16 melanoma 세포의 분화과정에서 이를 억제하는 효과를 주고 있음을 알 수 있었다. 이상의 결과들을 종합해 볼 때 melanoston은 $\alpha$-MSH에 진행되는 B16 세포의 분화를 억제하고 이 과정에서 멜라닌 생성의 주된 효소인 tyrosinase의 활성화를 억제하며 결과적으로는 멜라닌 생성을 저해하는 것으로 사료된다.

• 대한화장품학회지
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• 제31권1호
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• pp.25-33
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• 2005

본 연구에서는 효모에서 분리한 melanoston이라고 명명된 멜라닌 생성을 억제하는 물질의 작용 기전을 밝히기 위한 것이다. $\alpha$-MSH를 처리한 B16 melanoma 세포에서 melanoston은 tyrosinase mRNA 발현양을 $10\%$ 정도 저해되는데 그쳤으며 western blotting을 이용한 단백질 측정에서도 이와 비슷한 정도의 단백질 생성 억제를 보였다. 그러나 B16 세포 배양액에 melanoston을 첨가할 경우 세포내 tyrosinase 활성이 $30\%$까지 감소되는 것으로 나타나 melanoston이 tyrosinase inhibitor는 아니지만 세포내 tyrosinase 활성화(activation) 과정을 억제하는 것으로 추측할 수 있었다. 또한 광학 현미경을 이용한 morphology 관찰에서 $\alpha$-MSH를 처리한 세포에서는 많은 dentrite가 형성되면서 세포분화가 일어나는 반면 melanoston를 처리한 경우에는 dendrite가 감소하면서 세포형태가 대조군과 비슷하게 회복되는 것을 알 수 있었다. 또 FITC-anti-tyrosinase-Ab를 이용한 형광염색을 통해서는 $\alpha$-MSH만 처리한 세포에서는 tyrosinase의 분포가 dendrite를 포함한 세포 전체로 퍼져나가는 것을 관찰 할 수 있었고 $\alpha$-MSH와 melanoston을 동시에 처리한 세포에서는 대조군과 비슷하게 tyrosinase가 핵 주변에서만 관찰되어 melanoston이 B16 melanoma 세포의 분화과정에서 이를 억제하는 효과를 주고 있음을 알 수 있었다. 이상의 결과들을 종합해 볼 때 melanoston은 $\alpha$-MSH에 의해 진행되는 B16 세포의 분화를 억제하고 이 과정에서 멜라닌 생성의 주된 효소인 tyrosinase의 활성화를 억제하며 결과적으로는 멜라닌 생성을 저해하는 것으로 사료된다.