期刊
FOOD CHEMISTRY
卷 183, 期 -, 页码 49-57出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.foodchem.2015.03.016
关键词
Polyphenoloxidase; Tyrosinase activity; Grapes; Riesling; Dornfelder
资金
- Stiftung Rheinland-Pfalz fur Innovation, Germany
- NMFZ
- BMWi/FEI
Polyphenoloxidases (PPO) of the type-3 copper protein family are considered to be catecholoxidases catalyzing the oxidation of o-diphenols to their corresponding quinones. PPO from Grenache grapes has recently been reported to display only diphenolase activity. In contrast, we have characterized PPOs from Dornfelder and Riesling grapes which display both monophenolase and diphenolase activity. Ultracentrifugation and size exclusion chromatography indicated that both PPOs occur as monomers with M-r of about 38 kDa. Non-reducing SDS-PAGE shows two bands of about 38 kDa exhibiting strong activity. Remarkably, three bands up to 60 kDa displayed only very weak PPO activity, supporting the hypothesis that the C-terminal domain covers the entrance to the active site. Molecular dynamic analysis indicated that the hydroxyl group of monophenolic substrates can bind to CuA after the flexible but sterically hindering Phe 259 swings away on a picosecond time scale. (C) 2015 Elsevier 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