...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Kinetic Characterization of Prenyl-Flavin Synthase from ITSaccharomyces cerevisiaeIT
【24h】

Kinetic Characterization of Prenyl-Flavin Synthase from ITSaccharomyces cerevisiaeIT

机译：ITSaccharomyces cerevisiaeIT异戊二烯基黄素合酶的动力学表征

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We have characterized the kinetics and substrate requirements of prenyl-flavin synthase from yeast. This enzyme catalyzes the addition of an isopentenyl unit to reduced flavin mononucleotide (FMN) to form an additional six-membered ring that bridges NS and C6 of the flavin nucleus, thereby converting the flavin from a redox cofactor to one that supports the decarboxylation of aryl carboxylic acids. In contrast to bacterial enzymes, the yeast enzyme was found to use dimethylallyl pyrophosphate, rather than dimethylallyl phosphate, as the prenyl donor in the reaction. We developed a coupled assay for prenylflavin synthase activity in which turnover was linked to the activation of the prenyl-flavin-dependent enzyme, ferulic acid decarboxylase. The kinetics of the reaction are extremely slow: k(cat) = 12.2 +/- 0.2 11 h(-1), and K-M for dimethylallyl pyrophosphate = 9.8 +/- 0.7 mu M. The K-M for reduced FMN was too accurately measured. The kinetics of reduced FMN consumption were studied under pre-steady state conditions. The reaction of FMN was described well by first-order kinetics with a k(app) of 17.4 +/- 1.1 h(-1). These results indicate that a chemical step, most likely formation of the carbon-carbon bond between C6 of the flavin and the isopentenyl moiety, is substantially rate-determining in the reaction.
机译：我们已经表征了酵母中异戊二烯基-黄素合酶的动力学和底物要求。该酶催化异戊烯基单元添加到还原黄素单核苷酸 （FMN） 中，形成一个额外的六元环，该环桥接黄素核的 NS 和 C6，从而将黄素从氧化还原辅因子转化为支持芳基羧酸脱羧的辅因子。与细菌酶相比，酵母酶被发现使用二甲基烯丙基焦磷酸盐，而不是二甲基烯丙基磷酸酯作为反应中的异戊二烯基供体。我们开发了一种异戊烯黄素合酶活性的偶联测定法，其中周转与异戊二烯基黄素依赖性酶阿魏酸脱羧酶的激活有关。反应动力学极慢：k（cat） = 12.2 +/- 0.2 11 h（-1），二甲基烯丙基焦磷酸盐的K-M = 9.8 +/- 0.7 μ M。降低 FMN 的 K-M 测量得太精确了。研究了预稳态条件下FMN消耗降低的动力学。通过一级动力学很好地描述了FMN的反应，k（app）为17.4 +/- 1.1 h（-1）。这些结果表明，化学步骤，最有可能在黄素的C6和异戊烯基部分之间形成碳-碳键，在反应中基本上决定了速率。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号