• Natural Product Sciences
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• 제3권2호
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• pp.111-121
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• 1997

Tyrosinase catalyzes the rate-limiting steps in melanin biosynthesis which is involved in skin-coloring and local hyperpigmentation of human beings, and unfavorable darkening of food products, Inhibitory effects on 3,4-dihydroxy-phenylalanine (dopa) oxidase activity of tyrosinase by 594 kinds of herbal extracts prepared from herbal medicines and wild plants in Korea were estimated. Two herbal extracts prepared from radicis cortex of Morus alba and rhizoma of Curcuma longa were selected as those exhibiting potent inhibitory effects on the enzyme activity. These herbal extracts were subjected to sequential fractionations with methylene chloride, ethyl acetate, n-butanol, and polar residue. The inhibitory effects on dopa oxidase activity of tyrosinase were shown in ethyl acetate fraction of Morus alba, and in methylene chloride fraction of Curcuma langa. The ethyl acetate fraction of Marus alba exhibited 50% of inhibition on dopa oxidase activity of tyrosinase at the concentration of 12 ${\mu}g/ml$, and methylene chloride fraction of Curcuma langa at 51 ${\mu}g/ml$.

• Bulletin of the Korean Chemical Society
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• 제25권5호
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• pp.625-628
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• 2004

Ceruloplasmin (CP), the blue oxidase present in all vertebrates, is the major copper-containing protein of plasma. It has been proposed that oxidation of L-3,4-dihydroxyphenylalanine (DOPA) may contribute to the pathogenesis of neurodegenerative disorders. The effect of the oxidized products of DOPA on the modification of human CP was investigated. When CP was incubated with the oxidized L-DOPA, the protein was induced to be aggregated and ferroxidase activity was decreased in a time-dependent manner. Radical scavengers and catalase significantly inhibited the oxidized DOPA-mediated CP aggregation. Copper chelatrors, Diethylenetriaminepenta acetic acid (DTPA) and Diethyldithiocarbamic acid (DDC), also inhibited the oxidative modification of CP. The results suggested that DOPA oxidation led to the formation of free radical and induced the CP aggregation.

• 대한화장품학회지
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• 제30권4호
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• pp.485-489
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• 2004

피부에서 melanin은 자외선 차단의 주요한 역할을 한다. Tyrosinase는 멜라닌 생합성과정에서 초기 단계에 관여하는 중요한 효소로서 이것의 조절을 통한 피부 멜라닌화 억제에 관해 많은 연구가 되어져왔다. 본 연구에서는 해녀콩 추출물에서 mushroom tyrosinase 활성억제, B16F10 melanoma 세포를 이용한 dopa oxidase 활성억제 및 멜라닌 합성 억제 효과를 확인하였다. Tyrosinase mRNA 발현에서의 억제 효과를 확인하기 위하여 RT-PCR을 이용하였으며, $CHCI_3$ 층에서 분리해낸 A 분획에서 tyrosinase mRNA 발현을 억제시킴을 확인하였다.

• 한국식품과학회지
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• 제34권4호
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• pp.552-558
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• 2002

팽나무버섯(Flammulina velutipes)에서 polyphenol oxidase가 황산암모늄 침전법, Superdex G-75 겔여과크로마토그래피, Phenyl superose 친화크로마토그래피, Mono-Q 이온교환수지 크로마토그래피, 그리고 Superdex S-200 겔크로마토그래피 등의 과정으로 정제되었으며, 특성화 되었다. 정제된 효소의 비활성도는 199.1 units/mg으로 나타났으며, 이 효소는 40 kDa의 단일폴리펩티드 사슬로 구성되어 있음이 밝혀졌다. 효소반응의 최적 pH와 온도는 각각 6.0과 $25^{\circ}C$,이었으며, pH 3과 5 사이의 산성조건과, pH 8과 10 사이의 알카리 조건에서는 활성이 감소되거나 상실되었다. 이 효소는 L-DOPA와 caffeic acid 등의 o-diphenols류에 대하여 높은 효소활성을 나타내었으며, L-DOPA와 caffeic acid에 대한 Km 값은 각각 3.97mM과 1.78mM로 계산되었다. 2-mercaptoethanol, L-ascorbic acid, sodium bisulfite, EDTA와 $Mg^{2+}$은 팽나무버섯 pholyphenol oxidase의 효소활성을 감소시켰으며, $Cu^{2+}$, $Fe^{2+}$, $Zn^{2+}$ and $Ni^{2+}$ 등은 효소의 활성을 촉진하는 인자로 밝혀졌다. 정제된 효소는 $-70^{\circ}C$에서 3개월, 그리고 $-20^{\circ}C$에서 1개월간 활성의 손실 없이 저장이 가능하였다.

• Applied Biological Chemistry
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• 제34권1호
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• pp.49-53
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• 1991

참나물로부터 추출한 polyphenol oxidase의 부분정제를 $(NH_4)_2SO_4$, 처리 및 Sephadex G-150 column chromatography에 의해 분리하였다. Polyphenoloxidase의 최적 pH와 최적온도는 7.5와$30^{\circ}C$였으며, pH 6.5에서 $70^{\circ}C$에서 30분간 처리시와 $80^{\circ}C$에서 5분간 처리시 완전 실활하였다. Polyphenol oxidase는 ascorbic acid, glutathione, potassium cyanide(0.1mM)에 의해 불활성화되었으며 L-cysteine, potassium cyanide, ascorbic acid, glutathione(0.5, 1mM)에 의해서는 완전 실활되었다. Catechol과 3,4-dihydroxytoluene의 기질은 높은 특이성을 나타낸 반면 pyrogallol, dopamine, DL-dopa의 기질은 강하게 활성을 억제하였다. Polyphenol oxidase의 $K_m$ 값은 86.5mM이었다.

• The Korean Journal of Physiology and Pharmacology
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• 제3권2호
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• pp.147-155
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• 1999

Antioxidant effects of serotonin and L-DOPA on neuronal tissues were examined by studying the oxidative damages of brain synaptosomal components. The study further explored the mechanism by which they exert protective actions. Serotonin and L-DOPA (1 ${\mu}M$ to 1 mM) significantly inhibited lipid peroxidation of brain tissues by either $Fe^{2+}$ and ascorbate or t-butyl hydroperoxide in a dose dependent fashion. Protective effect of serotonin on the peroxidative actions of both systems was greater than that of L-DOPA. Protein oxidation of synaptosomes caused by $Fe^{2+}$ and ascorbate was attenuated by serotonin and L-DOPA. Protein oxidation more sensitively responded to L-DOPA rather than serotonin. Serotonin and L-DOPA (100 ${\mu}M$) decreased effectively the oxidation of synaptosomal sulfhydryl groups caused by $Fe^{2+}$ and ascorbate. The production of hydroxyl radical caused by either $Fe^{3+},$ EDTA, H_2O_2$ and ascorbate or xanthine and xanthine oxidase was significantly decreased by serotonin and L-DOPA (1 mM). Equal concentrations of serotonin and L-DOPA restored synaptosomal $Ca^{2+}$ uptake decreased by $Fe^{2+}$ and ascorbate, which is responsible for SOD and catalase. Protective effects of serotonin and L-DOPA on brain synaptosomes may be attributed to their removing action on reactive oxidants, hydroxyl radicals and probably iron-oxygen complex, without chelating action on iron.

• 약학회지
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• 제45권5호
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• pp.522-528
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• 2001

Tyrosinase plays an important role in the process of melanin biosynthesis, and it is a biochemical target enzyme for skin-whitening agents and the remedy for disturbances in pigmentation. We have screened 25 natural plant extracts for inhibitory effects against DOPA oxidase activity of tyrosinase. For the inhibitory effect against DOPA oxidase activity of tyrosinase, the recombinant human tyrosinase and the purified mushroom tyrosinase were used. Each of the dried plants extracted with methanol, and then the extracts were subjected to sequential fractionations with methylene chloride, ethyl acetate, n-butanol and water, respective The methylene chloride fractions of Angelica tenuissima, Nardostachys chinensis, Bombyx mop and Saposhnikovia divaricata, and the n-butanol fraction of Bombyx mori notably inhibited the human tyrosinase activity as well as mushroom tyrosinase activity (more than 90% inhibition). This study suggests that the above extracts have a potential as whitening agents as single ingredients or in combination with other of the extracts.

• 한국식품영양과학회지
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• 제20권3호
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• pp.241-245
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• 1991

참취로부터 추출한 poluphenol oxidase의 부분정제를 $(NH_4)_2SO_4$ 처리 및 Sephadex G-150 column chromatogaphy에 의해 분리하였다. Polypenol oxidase의 최적pH와 최적온도는 각각 7.0과 $30^{\circ}C$였으며, 효소활성은 $60^{\circ}C$에서 30분간 처리시와 $70^{\circ}C$에서 5분간 처리시 완전실활하였다. 기질특이성에서는 chlorogenic acid의 기질이 높은 특이성을 나타난 반면 DL-dopa는 활성을 억제하였다. Polyphenol oxidase의 Km값은 17.6mM이었다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2000년도 추계 학술발표회
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• pp.27.1-27
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• 2000

• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 NEW STRATEGY FOR DRUG DEVELOPMENT IN POST-GENOMIC ERA(대한약학회)
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• pp.232.2-232.2
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• 2000