Potent Inhibitory Effects of N-Aryl S-Alkylthiocarbamate Derivatives on the Dopa Oxidase Activity of Mushroom Tyrosinase

2005 ◽  
Vol 53 (7) ◽  
pp. 747-749 ◽  
Author(s):  
Kun Ho Lee ◽  
Mamoru Koketsu ◽  
Sang Yoon Choi ◽  
Kang Jin Lee ◽  
Pyeongjae Lee ◽  
...  
Keyword(s):  
Oxidase Activity ◽  
Mushroom Tyrosinase ◽  
Inhibitory Effects ◽  
Dopa Oxidase

Potent Inhibitory Effects of N-Aryl S-Alkylthiocarbamate Derivatives on the Dopa Oxidase Activity of Mushroom Tyrosinase.

ChemInform ◽  
2005 ◽  
Vol 36 (52) ◽  
Author(s):  
Kun Ho Lee ◽  
Mamoru Koketsu ◽  
Sang Yoon Choi ◽  
Kang Jin Lee ◽  
Pyeongjae Lee ◽  
...  
Keyword(s):  
Oxidase Activity ◽  
Mushroom Tyrosinase ◽  
Inhibitory Effects ◽  
Dopa Oxidase

Oxyresveratrol as the Potent Inhibitor on Dopa Oxidase Activity of Mushroom Tyrosinase

1998 ◽  
Vol 243 (3) ◽  
pp. 801-803 ◽  
Author(s):  
Nam-Ho Shin ◽  
Shi Yong Ryu ◽  
Eun Ju Choi ◽  
Seh-Hoon Kang ◽  
IL-Moo Chang ◽  
...  
Keyword(s):  
Oxidase Activity ◽  
Potent Inhibitor ◽  
Mushroom Tyrosinase ◽  
Dopa Oxidase

Inhibition of Melanogenesis in Murine B16/F10 Melanoma Cells by Ligusticum sinensis Oliv.

2006 ◽  
Vol 34 (03) ◽  
pp. 523-533 ◽  
Author(s):  
Ching-Yuan Wu ◽  
Jong-Hwei S. Pang ◽  
Sheng-Teng Huang
Keyword(s):  
Mrna Expression ◽  
Oxidase Activity ◽  
Underlying Mechanism ◽  
Inhibitory Effect ◽  
Melanoma Cells ◽  
Dependent Manner ◽  
Mushroom Tyrosinase ◽  
Tyrosinase Gene ◽  
Direct Inhibitory Effect ◽  
Dopa Oxidase

Ligusticum sinensis Oliv. (LSO) is an herbal drug commonly used as a topical treatment of epidermal hyperdepigmentation in Chinese medicine. However, the mechanism underlying the depigmentation by LSO is still unclear. The purpose of this study was to investigate the effects of LSO on the process of melanogenesis and its possible underlying mechanism. Suppressed DOPA oxidase activity of mushroom tyrosinase was first noted when incubated with aqueous extracts of LSO, demonstrating the direct inhibitory effect of LSO on mushroom tyrosinase. Further experiments were carried out in murine B16/F10 melanoma cells and the effects of LSO extract on melanin formation, tyrosinase activity and tyrosinase gene expression were tested. Under conditions without affecting the viability of murine B16/F10 melanoma cells, LSO extract significantly reduced the cellular melanin content in a dose-dependent manner. The DOPA oxidase activity of tyrosinase in B16/F10 cells was dose-dependently inhibited by LSO treatment, possibly mediated by the suppressed tyrosinase mRNA expression in LSO-treated B16/F10 cells. In conclusion, the inhibitory effect of LSO on melanogenesis is likely associated with decreased DOPA oxidase activity of tyrosinase that is most likely the result of the down-regulation of tyrosinase mRNA expression.

Some Commercial Azo Dyes as Inhibitors of Mushroom Tyrosinase DOPA Oxidase Activity

2007 ◽  
Vol 2 (8) ◽  
pp. 718-724 ◽  
Author(s):  
Shiv Kumar Dubey ◽  
Archana Pandey . ◽  
Ashok Kumar Bajaj . ◽  
and Krishna Misra .
Keyword(s):  
Azo Dyes ◽  
Oxidase Activity ◽  
Mushroom Tyrosinase ◽  
Dopa Oxidase

Inhibitory Effects of Substituted Cinnamic Acid Esters on Mushroom Tyrosinase

2013 ◽  
Vol 10 (6) ◽  
pp. 529-534 ◽  
Author(s):  
Zhenghua Zhang ◽  
Jinbing Liu ◽  
Fengyan Wu ◽  
Liangzhong Zhao
Keyword(s):  
Cinnamic Acid ◽  
Mushroom Tyrosinase ◽  
Inhibitory Effects ◽  
Acid Esters

Mechanism of inhibition of succinate oxidase by products of oxidation of o-dihydroxycoumarins

1980 ◽  
Vol 45 (2) ◽  
pp. 641-652
Author(s):  
Petr Zbořil
Keyword(s):  
Inhibitory Activity ◽  
Oxidase Activity ◽  
Enzyme Preparation ◽  
Inhibitory Effects ◽  
Anaerobic Conditions ◽  
Long Period ◽  
Mechanism Of Inhibition ◽  
Intermediary Product ◽  
Succinate Oxidase ◽  
By Products

Semiquinone is an intermediary product of the oxidation of daphnetin (7,8-dihydroxycoumarin) and esculetin (6,7-dihydroxycoumarin) by diphenol oxidase; its concentration rapidly decreases. When the oxidation is effected by ferricytochrome c, the concentration of the semiquinone remains practically constant for a long period. Similarly, the ability of the products of daphnetin oxidation by diphenol oxidase to inhibit succinate oxidase activity in mitochondrial fragments rapidly decreases with time; the decrease is considerably slower in the case of cytochrome c. The inhibitory activity of the product decreases with time also during esculetin oxidation by ferricyanide. This indicates that the inhibitory effects must be ascribed predominantly to the semiquinone, the quinone is less efficient. The inhibition of succinate oxidase or succinate dehydrogenase was strongly decreased when the enzyme preparation of Keilin and Hartree was incubated with esculetin and ferricyanide in the presence of KCN or under anaerobic conditions. This demonstrates that the reaction of the inhibitor with the enzyme either involves subsequent oxidations or that the inhibitor preferentially reacts with the oxidized form of the sensitive component of the respiratory chain. The second alternative is very little probable since there is no correlation between the degree of inhibition and the binding of the inhibitor to mitochondrial fragments.

scholarly journals Oxidation of monohydric phenol substrates by tyrosinase. An oximetric study

1992 ◽  
Vol 288 (1) ◽  
pp. 63-67 ◽  
Author(s):  
S Naish-Byfield ◽  
P A Riley
Keyword(s):  
Oxygen Consumption ◽  
Maximum Rate ◽  
Low Ph ◽  
Molar Ratio ◽  
Lag Phase ◽  
Complete Oxidation ◽  
Mushroom Tyrosinase ◽  
Tyrosine Oxidation ◽  
Rate Of Reaction ◽  
Dopa Oxidase

The purity of commercially available mushroom tyrosinase was investigated by non-denaturing PAGE. Most of the protein in the preparation migrated as a single band under these conditions. This band contained both tyrosinase and dopa oxidase activity. No other activity of either classification was found in the preparation. Oxygen consumption by tyrosinase during oxidation of the monohydric phenol substrates tyrosine and 4-hydroxyanisole (4HA) was monitored by oximetry in order to determine the stoichiometry of the reactions. For complete oxidation, the molar ratio of oxygen: 4HA was 1:1. Under identical conditions, oxidation of tyrosine required 1.5 mol of oxygen/mol of tyrosine. The additional oxygen uptake during tyrosine oxidation is due to the internal cyclization of dopaquinone to form cyclodopa, which undergoes a redox reaction with dopaquinone to form dopachrome and dopa, which is then oxidized by the enzyme, leading to an additional 0.5 mol of oxygen/mol of original substrate. Oxygen consumption for complete oxidation of 200 nmol of 4HA was constant over a range of concentrations of tyrosinase of 33-330 units/ml of substrate. The maximum rate of reaction was directly proportional to the concentration of tyrosinase, whereas the length of the lag phase decreased non-linearly with increasing tyrosinase concentration. Activation of the enzyme by exposure to citrate was not seen, nor was the lag phase abolished by exposure of the enzyme to low pH. Michaelis-Menten analysis of tyrosinase in which the lag phase is abolished by pre-exposure of the enzyme to a low concentration of dithiothreitol gave Km values for tyrosine and 4HA of 153 and 20 microM respectively.

scholarly journals The Development of Dopa Oxidase Activity in the Skin and in the Hair Cycle

1961 ◽  
Vol 1961 (2) ◽  
pp. 190-194
Author(s):  
Ken HASHIMOTO ◽  
Kazuo OGAWA ◽  
Walter F. LEVER
Keyword(s):  
Oxidase Activity ◽  
Hair Cycle ◽  
Dopa Oxidase
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