Resveratrol and a Novel Tyrosinase in Carignan Grape Juice
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- 作者：Regev Gilly ; Dekel Mara ; Shoseyov Oded ; and Kerem Zohar
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2001
- 出版时间：March 2001
- 年：2001
- 卷：49
- 期：3
- 页码：1479 - 1485
- 全文大小：171K
- 年卷期：v.49,no.3(March 2001)
- ISSN：1520-5118
文摘
Polyphenol levels in wines are affected by the wine-making process. Resveratrol is one polyphenolwhich has been the subject of a commendable amount of recent research. In this work, we foundthat resveratrol is immediately degraded by tyrosinase. A novel tyrosinase was purified fromCarignan grapes. The purification process included salting out and separation on a cation-exchangecolumn, followed by gel filtration. Tyrosinase was purified in a homogeneous form by SDS-PAGEand was characterized: its specific activity toward 3-(3,4-dihydroxyphenyl)-L-alanine (DOPA)increased by a factor of 24 with an overall recovery of 3% of initial activity. The apparent molecularmass of the purified tyrosinase was 40 kDa as determined by SDS-PAGE, and 42 kDa as determinedby gel filtration. Its activity was optimal at pH 6 and at 25 
C. The enzyme exhibited high activitytoward phenylenediamine, epicatechin, pyrogallol, DOPA, and resveratrol. Tyrosinase activity wasinhibited by KCN, thiourea, and SO2. Resveratrol levels were stable following the removal of proteinsfrom the juice, suggesting that early spraying of grapes with SO2 is an important factor affectingthe final amount of resveratrol in wine.Keywords: Resveratrol; tyrosinase; wine; grape; Vitis vinifera cv. Carignan
C. The enzyme exhibited high activitytoward phenylenediamine, epicatechin, pyrogallol, DOPA, and resveratrol. Tyrosinase activity wasinhibited by KCN, thiourea, and SO2. Resveratrol levels were stable following the removal of proteinsfrom the juice, suggesting that early spraying of grapes with SO2 is an important factor affectingthe final amount of resveratrol in wine.Keywords: Resveratrol; tyrosinase; wine; grape; Vitis vinifera cv. Carignan