...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of bacteriology >Diversion of the Metabolic Flux from Pyruvate Dehydrogenase to Pyruvate Oxidase Decreases Oxidative Stress during Glucose Metabolism in Nongrowing Escherichia coli Cells Incubated under Aerobic, Phosphate Starvation Conditions
【24h】

Diversion of the Metabolic Flux from Pyruvate Dehydrogenase to Pyruvate Oxidase Decreases Oxidative Stress during Glucose Metabolism in Nongrowing Escherichia coli Cells Incubated under Aerobic, Phosphate Starvation Conditions

机译：代谢通量从丙酮酸脱氢酶转移到丙酮酸氧化酶减少了在有氧，磷酸盐饥饿条件下培养的非生长大肠杆菌细胞葡萄糖代谢过程中的氧化应激。

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Ongoing aerobic metabolism in nongrowing cells may generate oxidative stress. It is shown here that the levels of thiobarbituric acid-reactive substances (TBARSs), which measure fragmentation products of oxidized molecules, increased strongly at the onset of starvation for phosphate (Pi). This increase in TBARS levels required the activity of the histone-like nucleoid-structuring (H-NS) protein. TBARS levels weakly increased further in ΔahpCF mutants deficient in alkyl hydroperoxide reductase (AHP) activity during prolonged metabolism of glucose to acetate. Inactivation of pyruvate oxidase (PoxB) activity decreased the production of acetate by half and significantly increased the production of TBARS. Overall, these data suggest that during incubation under aerobic, Pi starvation conditions, metabolic flux is diverted from the pyruvate dehydrogenase (PDH) complex (NAD dependent) to PoxB (NAD independent). This shift may decrease the production of NADH and in turn the adventitious production of H2O2 by NADH dehydrogenase in the respiratory chain. The residual low levels of H2O2 produced during prolonged incubation can be scavenged efficiently by AHP. However, high levels of H2O2 may be reached transiently at the onset of stationary phase, primarily because H-NS may delay the metabolic shift from PDH to PoxB.
机译：非生长细胞中正在进行的有氧代谢可能产生氧化应激。结果表明，用于测量氧化分子碎片产物的硫代巴比妥酸反应性物质（TBARSs）的水平在磷酸盐饥饿时开始显着增加（P i ）。 TBARS水平的这种增加需要组蛋白样核苷酸结构（H-NS）蛋白的活性。在葡萄糖长时间代谢为乙酸盐期间，缺乏烷基氢过氧化物还原酶（AHP）活性的Δ ahpCF 突变体中，TBARS的水​​平进一步微弱增加。丙酮酸氧化酶（PoxB）活性的失活将乙酸盐的产生减少了一半，并显着增加了TBARS的产生。总体而言，这些数据表明，在有氧的P i 饥饿条件下温育期间，代谢通量从丙酮酸脱氢酶（PDH）复合物（NAD依赖）转移到PoxB（NAD独立）。这种转变可能会减少NADH的产生，进而降低呼吸链中NADH脱氢酶不定产生H 2 O 2 的可能性。 AHP可以有效地消除长时间孵育过程中产生的残留的H 2 O 2 低水平。然而，高水平的H 2 O 2 可能在静止期开始时短暂达到，这主要是因为H-NS可能延迟了从PDH到PoxB的代谢转变。

著录项

相似文献

  • 外文文献
  • 中文文献
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