ubiquinol-8 | 74075-00-6

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 异戊烯醇脂质
• 英文名称: ubiquinol-8
• 英文别名: reduced coenzyme Q8；ubiquinol (40)；2,3-dimethoxy-5-methyl-6-[(2E,6E,10E,14E,18E,22E,26E)-3,7,11,15,19,23,27,31-octamethyldotriaconta-2,6,10,14,18,22,26,30-octaenyl]benzene-1,4-diol
• CAS: 74075-00-6
• 化学式: C₄₉H₇₆O₄
• 分子量: 729.14
• InChiKey: LOJUQFSPYHMHEO-SGHXUWJISA-N

物化性质

• 沸点：
  784.9±60.0 °C(Predicted)
• 密度：
  0.961±0.06 g/cm3(Predicted)
• 物理描述：
  Solid

计算性质

• 辛醇/水分配系数(LogP)：
  16.4
• 重原子数：
  53
• 可旋转键数：
  25
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.55
• 拓扑面积：
  58.9
• 氢给体数：
  2
• 氢受体数：
  4

反应信息

• 作为反应物：
  描述：

  硝酸钾 、 ubiquinol-8 生成 水 、 亚硝酸盐 、 辅酶Q8
  参考文献：
  名称：

  NapGH components of the periplasmic nitrate reductase of Escherichia coli K-12: location, topology and physiological roles in quinol oxidation and redox balancing

  摘要：

  许多细菌的 Nap（周质硝酸还原酶）操作子包括四个常见的基本组成部分：napD、napA、napB 和 napC（或 napC 的同源物）。在大肠杆菌中，还有三个基因：napF、napG 和 napH，但它们都不是 Nap 活性所必需的。我们现在的研究表明，在萘醌合成缺陷菌株中，napG 或 napH 的缺失几乎消除了 Nap 依赖性硝酸盐还原。残余的硝酸盐还原率（约为 napG+H+ 菌株的 1%）足以取代富马酸还原，在葡萄糖发酵的生长过程中发挥氧化还原平衡作用。Western 印迹法结合 β-半乳糖苷酶和碱性磷酸酶融合实验证实，NapH 是一种具有四个跨膜螺旋的整体膜蛋白。N 端和 C 端以及两个非血红素铁硫中心都位于细胞质中。研究表明，N末端的精氨酸孪生基团对NapG的功能至关重要，这与NapG通过精氨酸孪生基团转运途径分泌到外质的预期一致。细菌双杂交系统显示，NapH 可能在细胞质一侧或膜内与 NapC 相互作用。正如预期的那样，在细胞质中，NapG 与 NapC 或 NapH 没有相互作用。一种体外喹啉脱氢酶试验表明，NapG 和 NapH 对于从红豆杉醇到终端 NapAB 复合物的快速电子传递都是必不可少的。这些新的体内和体外研究结果证实，NapG 和 NapH 形成了一种醌脱氢酶，将高中点氧化还原电位的泛醌-泛醌醇偶联物的电子转移通过 NapC 和 NapB 传导到 NapA。

  DOI：

  10.1042/bj20031115
• 作为产物：
  描述：

  辅酶Q8 在 sodium tetrahydroborate 作用下， 以 甲醇 、 正己烷 为溶剂， 反应 0.08h， 生成 ubiquinol-8
  参考文献：
  名称：

  A genome-wide screen in Escherichia coli reveals that ubiquinone is a key antioxidant for metabolism of long-chain fatty acids

  摘要：

  Long-chain fatty acids (LCFAs) are used as a rich source of metabolic energy by several bacteria including important pathogens. Because LCFAs also induce oxidative stress, which may be detrimental to bacterial growth, it is imperative to understand the strategies employed by bacteria to counteract such stresses. Here, we performed a genetic screen in Escherichia coli on the LCFA, oleate, and compared our results with published genome-wide screens of multiple non-fermentable carbon sources. This large-scale analysis revealed that among components of the aerobic electron transport chain (ETC), only genes involved in the biosynthesis of ubiquinone, an electron carrier in the ETC, are highly required for growth in LCFAs when compared with other carbon sources. Using genetic and biochemical approaches, we show that this increased requirement of ubiquinone is to mitigate elevated levels of reactive oxygen species generated by LCFA degradation. Intriguingly, we find that unlike other ETC components whose requirement for growth is inversely correlated with the energy yield of non-fermentable carbon sources, the requirement of ubiquinone correlates with oxidative stress. Our results therefore suggest that a mechanism in addition to the known electron carrier function of ubiquinone is required to explain its antioxidant role in LCFA metabolism. Importantly, among the various oxidative stress combat players in E. coli, ubiquinone acts as the cell's first line of defense against LCFA-induced oxidative stress. Taken together, our results emphasize that ubiquinone is a key antioxidant during LCFA metabolism and therefore provides a rationale for investigating its role in LCFA-utilizing pathogenic bacteria.

  DOI：

  10.1074/jbc.m117.806240

文献信息

• Ubiquinone biosynthesis in microorganisms
  作者：R Meganathan

  DOI：10.1111/j.1574-6968.2001.tb10831.x

  日期：2001.9

  The quinoid nucleus of the benzoquinone, ubiquinone (coenzyme Q; Q), is derived from the shikimate pathway in bacteria and eukaryotic microorganisms. Ubiquinone is not considered a vitamin since mammals synthesize it from the essential amino acid tyrosine. Escherichia coli and other Gram-negative bacteria derive the 4-hydroxybenzoate required for the biosynthesis of Q directly from chorismate. The yeast, Saccharomyces cerevisiae, can either form 4-hydroxybenzoate from chorismate or tyrosine. However, unlike mammals, S. cerevisiae synthesizes tyrosine in vivo by the shikimate pathway. While the reactions of the pathway leading from 4-hydroxybenzoate to Q are the same in both organisms the order in which they occur differs. The 4-hydroxybenzoate undergoes a prenylation, a decarboxylation and three hydroxylations alternating with three methylation reactions, resulting in the formation of Q. The methyl groups for the methylation reactions are derived from S-adenosylmethionine. While the prenyl side chain is formed by the 2-C-methyl-d-erythritol 4-phosphate (non-mevalonate) pathway in E. coli, it is formed by the mevalonate pathway in the yeast.

  苯醌的喹啉核，即泛醌（辅酶Q；Q），来源于细菌和真核微生物中的黄嘌呤代谢途径。泛醌并非维生素，因为哺乳动物从必需氨基酸酪氨酸中合成它。大肠杆菌和其他革兰氏阴性细菌直接从蝶呤中获取生物合成Q所需的4-羟基苯甲酸。酿酒酵母菌（Saccharomyces cerevisiae）可以从蝶呤或酪氨酸中形成4-羟基苯甲酸。然而，与哺乳动物不同，酿酒酵母菌通过黄嘌呤代谢途径在体内合成酪氨酸。虽然从4-羟基苯甲酸到Q的途径反应在两种生物中是相同的，但发生顺序不同。4-羟基苯甲酸经历一个异戊二烯化、一个脱羧和三个羟基化反应，与三个甲基化反应交替进行，最终形成Q。甲基化反应的甲基来自S-腺苷甲硫氨酸。虽然异戊二烯侧链在大肠杆菌中通过2-C-甲基-D-赤藓醇4-磷酸（非甲基戊二酸）途径形成，但在酵母菌中通过甲基戊二酸途径形成。
• Structural and Biochemical Evidence for an Enzymatic Quinone Redox Cycle in Escherichia coli
  作者：Melanie A. Adams、Zongchao Jia

  DOI：10.1074/jbc.m412637200

  日期：2005.3

  enzymatic reaction. We therefore refer to YgiN as quinol monooxygenase. Modulator of drug activity B is reported to be involved in the protection of cells from reactive oxygen species formed during single electron oxidation and reduction reactions. The enzymatic activities, together with the structural characterization of YgiN, lend evidence to the possible existence of a novel quinone redox cycle in E

  天然合成的醌具有多种重要的细胞功能。大肠杆菌同时产生泛醌和甲萘醌，它们参与电子传递。但是，在这些化合物的单电子还原过程中以及通过羟基醌产物的自氧化产生的半醌中间体会产生活性氧，从而对细胞产生压力。在这里，我们介绍了迄今未知功能的蛋白质YgiN的晶体结构。YgiN的三维折叠类似于ActVA-Orf6单加氧酶，后者作用于羟基醌底物。YgiN与“药物活性B的调节剂”共享一个启动子，该蛋白的活性类似于能够还原二甲酮的哺乳动物DT-黄递酶的活性。YgiN能够重新氧化薄荷脑，
• Functions of the Membrane-Associated and Cytoplasmic Malate Dehydrogenases in the Citric Acid Cycle of <i>Escherichia coli</i>
  作者：Michel E. van der Rest、Christian Frank、Douwe Molenaar

  DOI：10.1128/jb.182.24.6892-6899.2000

  日期：2000.12.15

  mqo expression. On the contrary, MQO and MDH are active at the same time in E. coli. For Corynebacterium glutamicum, it was found that MQO is the principal enzyme catalyzing the oxidation of malate to oxaloacetate. These observations justified a reinvestigation of the roles of MDH and MQO in the citric acid cycle of E. coli. In this organism, a defined deletion of the mdh gene led to severely decreased

  大肠杆菌中苹果酸氧化为草酰乙酸可以通过两种酶催化：众所周知的NAD依赖性苹果酸脱氢酶（MDH; EC 1.1.1.37）和膜相关的苹果酸：醌-氧化还原酶（MQO; EC 1.1.99.16） ，由基因mqo（以前称为yojH）编码。mqo基因的表达以及因此的MQO活性受碳和生长能源的调节。在分批培养中，MQO活性在指数生长期间最高，而在固定相开始后急剧下降。将β-半乳糖苷酶报告基因与mqo基因启动子融合的实验表明，其转录受ArcA-ArcB两组分系统调控。与早期报道相反，MDH不能抑制mqo表达。相反，MQO和MDH在大肠杆菌中同时具有活性。对于谷氨酸棒杆菌，发现MQO是催化苹果酸氧化为草酰乙酸的主要酶。这些观察结果证明对MDH和MQO在大肠杆菌柠檬酸循环中的作用进行了重新研究。在这种生物中，mdh基因的明确缺失导致在几种底物上的生长速率大大降低。mqo基因的缺失不会对生长速率产生明显的影
• EP1415969
  申请人：——

  公开号：——

  公开（公告）日：——
• STABILIZED COMPOSITION COMPRISING REDUCED COENZYME Q10
  申请人：KANEKA CORPORATION

  公开号：EP1452174B1

  公开（公告）日：2013-12-18