...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Redox control of the catalytic cycle of flavocytochrome P-450 BM3
【24h】

Redox control of the catalytic cycle of flavocytochrome P-450 BM3

机译：黄酮核催化循环氧化还原控制P-450 BM3

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

Flavocytochrome P-450 BM3 from Bacillus megaterium is a 119 kDa polypeptide whose heme and diflavin domains are fused to produce a catalytically self-sufficient fatty acid monooxygenase. Redox potentiometry studies have been performed with intact flavocytochrome P-450 BM3 and with its component heme, diflavin, FAD, and FMN domains. Results indicate that electron flow occurs from the NADPH donor through FAD, then FMN and on to the heme center where fatty acid substrate is bound and monooxygenation occurs. Prevention of futile cycling of electrons is avoided through an increase in redox potential of more than 100 mV caused by binding of fatty acids to the active site of P-450. Redox potentials are little altered for the component domains with respect to their values in the larger constructs, providing further evidence for the discrete domain organization of this flavocytochrome. The reduction potentials of the 4-electron reduced diflavin domain and 2-electron reduced FAD domain are considerably lower than those for the blue FAD semiquinone species observed during reductive titrations of these enzymes and that of the physiological electron donor (NADPH), indicating that the FAD hydroquinone is thermodynamically unfavorable and does not accumulate under turnover conditions. In contrast, the FMN hydroquinone is thermodynamically more favorable than the semiquinone.
机译：来自Bacillus MegaTium的黄酮粒细胞P-450 BM3是一种119kDa多肽，其血红素和二酰胺域融合以产生催化自给式脂肪酸单氧酶。已经用完整的黄胶质粒子P-450 BM3进行了氧化还原电位研究，并用其组分血红素，二酰胺，FAD和FMN结构域进行。结果表明，电子流量通过FAD从NADPH供体发生，然后FMN和ON到血红素中心，其中脂肪酸底物结合并发生单氧化。通过在P-450的活性位点与脂肪酸结合到100mV引起的氧化还原电位的氧化还原电位增加，避免了预防电子循环。对于在较大构建体中，氧化还原电位对于组分结构域几乎没有改变它们的值，为该黄鳞菌的离散结构域组织提供了进一步的证据。 4-电子还原的Divlavin结构域和2-电子还原的FAD结构域的减少电位显着低于在这些酶的还原滴定期间观察到的蓝色FAD半醌物种的电位和生理电子供体（NADPH）的那些，表明该FAD氢醌在热力学上不利，不会在营业额条件下积累。相反，FMN氢醌在热力学上比SECIQUINONE更有利。

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