期刊
PHYTOCHEMISTRY
卷 54, 期 5, 页码 481-487出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/S0031-9422(00)00125-4
关键词
inhibition of enzymatic browning; (-)-epicatechin; 2 '-(2-hydroxyethylthio)-(-)-epicatechin; 5 '-(2-hydroxyethylthio)-(-)-epicatechin; 2 ',5 '-bis(2-hydroxyethylthio)-(-)-epicatechin; polyphenol oxidase; polyphenolic compound; O-quinone; sulfhydryl enzyme; thiol compound
In a reaction between (-)-epicatechin (EC) and 2-mercaptoethanol (2ME), catalyzed by partially purified polyphenol oxidase (PPO) extracted from the style of Rhododendron mucronatum, 2'-(2-hydroxyethylthio)-(-)-epicatechin (2'-HETEC), 5'-(2-hydroxyethylthio)-(-)-epicatechin (5'-HETEC), and 2',5'-bis(2-hydroxyethylthio)-(-)-epicatechin (2',5'-HETEC) were formed. The rate of formation of 2',5'-HETEC from 5'-HETEC was faster than that from 2'-HETEC. In the absence of 2ME, the concentration of EC decreased rapidly and the reaction mixture turned brown; 2'-, 5'-, and 2',5'-HETEC, especially 2'-substituted HETECs, reacted more slowly. These data indicate that 2ME acts both as an inhibitor of the polymerization of O-quinone, presumably by binding to it and as a reductant involved in the conversion of O-quinone to O-dihydroxyphenol. Inhibition of enzymatic browning by other thiol compounds such as cysteine and dithiothreitol was also investigated. (C) 2000 Elsevier Science Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据