Citraconate

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 脂肪酰基
• 英文名称: Citraconate
• 英文别名: Citraconate(2-)；(Z)-2-methylbut-2-enedioate
• 化学式: C₅H₄O₄
• 分子量: 128.084
• InChiKey: HNEGQIOMVPPMNR-IHWYPQMZSA-L

计算性质

• 辛醇/水分配系数(LogP)：
  1.2
• 重原子数：
  9
• 可旋转键数：
  0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.2
• 拓扑面积：
  80.3
• 氢给体数：
  0
• 氢受体数：
  4

反应信息

• 作为反应物：
  描述：

  Citraconate 、 水 生成 (2R,3S)-3-Methylmalate
  参考文献：
  名称：

  詹氏甲烷球菌中丙酮酸生成2-氧代丁酸酯的途径的酶学和演化。

  摘要：

  古代甲烷甲烷球菌使用三种不同的2-含氧酸延长途径，这些途径延长了亮氨酸，异亮氨酸和辅酶B生物合成中前体的链长。在这些途径的每一种中，乌头酸酶型水解酶催化羟酸异构化反应。詹氏甲烷球菌的基因组序列编码形成水解酶的每个大亚基和小亚基的两个同源物，但是这些基因不是共转录的。这些基因彼此之间比以前表征的苹果酸异丙酯异构酶或高纯硝酸酶基因更相似。为了鉴定这些同源物的功能，亚单位的四种组合在大肠杆菌中异源表达，纯化并重建以产生全酶的铁硫中心。只有MJ0499和MJ1277蛋白的组合才能催化苹果酸异丙酯和柠檬酸酯的异构化反应。该对还使用柠檬酸柠檬酸酯和马来酸酯催化水合半反应。另一种广泛特异性的酶，苹果酸异丙酯脱氢酶（MJ0720）催化β-异丙基苹果酸，β-甲基苹果酸和d-苹果酸的氧化脱羧。结合这些结果，系统发育分析表明，丙酮酸通向2-氧代丁酸的途径（异亮氨酸生物合成中苏氨酸脱水酶的替代物）在细菌和古细菌中

  DOI：

  10.1128/jb.00166-07
• 作为产物：
  描述：

  柠康酸 、 alkaline earth salt of/the/ methylsulfuric acid 在 氢氧化钾 、 dipotassium hydrogenphosphate 作用下， 以 二氯甲烷 、 水 为溶剂， 反应 2.33h， 生成 Citraconate
  参考文献：
  名称：

  Dicarboxylic Acids Link Proton Transfer Across a Liquid Membrane to the Synthesis of Acyl Phosphates. A Model for P-Type H+-ATPases

  摘要：

  H+-ATPases are ion pumps that link proton transfer across cell membranes to the synthesis or hydrolysis of ATP. A current research goal is to understand the molecular-level mechanism of this linking. We present a chemical model that mimics some features of H+-ATPases by linking proton transfer across a liquid membrane to the synthesis of acyl phosphates using carboxylic acid anhydride intermediates. Citraconic acid (cis-2-methyl-2-butenedioic acid) accelerated the transfer of protons from a pH 0.3 solution across a chloroform liquid membrane to a pH 10 solution. The mechanism involved spontaneous formation of a small amount of citraconic anhydride (0.6%) in the pH 0.3 layer. This anhydride partitioned into the chloroform layer and diffused to the pH 10 layer, where it hydrolyzed, generating two protons. When the pH 10 layer contained phosphate (1.0 M), some of the citraconic anhydride reacted with phosphate to form citraconyl phosphate, 5.0% yield. In separate experiments, we confirmed that citraconyl phosphate had high phosphoryl donor potential by reacting it with morpholine to form a phosphoramidate (11.5% yield) or with fluoride to form fluorophosphonate (32% yield). To demonstrate the link between an acyl phosphate and a proton gradient in the reverse direction, we used succinyl phosphate, whose hydrolysis occurs in two steps: formation of succinic anhydride, which consumes protons, followed by hydrolysis of succinic anhydride, which releases protons. We generated a pH gradient by carrying out these two steps in separate solutions. Hydrolysis of succinyl phosphate (3.9 mmol) at pH 6.00 started with a increase in pH to 6.16 (0.59 mmol of H+ consumed) caused by the formation of succinic anhydride. We extracted this anhydride with dichloromethane and transferred it to a separate solution at pH 6.05. Hydrolysis of the anhydride released protons (0.36 mmol), decreasing the pH to 5.23. Our model suggests that H+-ATPases could use acyl phosphates and carboxylic acid anhydride intermediates to link proton transfer to ATP synthesis or hydrolysis.

  DOI：

  10.1021/jo00092a023
• 作为试剂：
  描述：

  柠康酸酐 、 2-乙基己醇 、 p-toluenesulfonic acid 、 乙酸乙酯 在 柠康酸酐 、 2-乙基己醇 、 碳酸氢钠 、 水 、 magnesium sulfate 、 Citraconate 作用下， 反应 16.0h， 生成 di(2-Ethylhexyl) (2Z)-2-methyl-2-butenedioate
  参考文献：
  名称：

  Catalyst component

  摘要：

  该发明涉及一种制备二价金属/过渡金属烯烃聚合催化剂组分的过程，其以无传统邻苯二甲酸酯电子给体的颗粒形式存在，并在烯烃聚合过程中使用。

  公开号：

  US08901261B2

文献信息

• Dicarboxylic Acids Link Proton Transfer Across a Liquid Membrane to the Synthesis of Acyl Phosphates. A Model for P-Type H+-ATPases
  作者：Ian. J. Colton、Romas J. Kazlauskas

  DOI：10.1021/jo00092a023

  日期：1994.7

  H+-ATPases are ion pumps that link proton transfer across cell membranes to the synthesis or hydrolysis of ATP. A current research goal is to understand the molecular-level mechanism of this linking. We present a chemical model that mimics some features of H+-ATPases by linking proton transfer across a liquid membrane to the synthesis of acyl phosphates using carboxylic acid anhydride intermediates. Citraconic acid (cis-2-methyl-2-butenedioic acid) accelerated the transfer of protons from a pH 0.3 solution across a chloroform liquid membrane to a pH 10 solution. The mechanism involved spontaneous formation of a small amount of citraconic anhydride (0.6%) in the pH 0.3 layer. This anhydride partitioned into the chloroform layer and diffused to the pH 10 layer, where it hydrolyzed, generating two protons. When the pH 10 layer contained phosphate (1.0 M), some of the citraconic anhydride reacted with phosphate to form citraconyl phosphate, 5.0% yield. In separate experiments, we confirmed that citraconyl phosphate had high phosphoryl donor potential by reacting it with morpholine to form a phosphoramidate (11.5% yield) or with fluoride to form fluorophosphonate (32% yield). To demonstrate the link between an acyl phosphate and a proton gradient in the reverse direction, we used succinyl phosphate, whose hydrolysis occurs in two steps: formation of succinic anhydride, which consumes protons, followed by hydrolysis of succinic anhydride, which releases protons. We generated a pH gradient by carrying out these two steps in separate solutions. Hydrolysis of succinyl phosphate (3.9 mmol) at pH 6.00 started with a increase in pH to 6.16 (0.59 mmol of H+ consumed) caused by the formation of succinic anhydride. We extracted this anhydride with dichloromethane and transferred it to a separate solution at pH 6.05. Hydrolysis of the anhydride released protons (0.36 mmol), decreasing the pH to 5.23. Our model suggests that H+-ATPases could use acyl phosphates and carboxylic acid anhydride intermediates to link proton transfer to ATP synthesis or hydrolysis.
• Enzymology and Evolution of the Pyruvate Pathway to 2-Oxobutyrate in <i>Methanocaldococcus jannaschii</i>
  作者：Randy M. Drevland、Abdul Waheed、David E. Graham

  DOI：10.1128/jb.00166-07

  日期：2007.6.15

  broad-specificity enzyme, isopropylmalate dehydrogenase (MJ0720), catalyzed the oxidative decarboxylation of beta-isopropylmalate, beta-methylmalate, and d-malate. Combined with these results, phylogenetic analysis suggests that the pyruvate pathway to 2-oxobutyrate (an alternative to threonine dehydratase in isoleucine biosynthesis) evolved several times in bacteria and archaea. The enzymes in the isopropylmalate

  古代甲烷甲烷球菌使用三种不同的2-含氧酸延长途径，这些途径延长了亮氨酸，异亮氨酸和辅酶B生物合成中前体的链长。在这些途径的每一种中，乌头酸酶型水解酶催化羟酸异构化反应。詹氏甲烷球菌的基因组序列编码形成水解酶的每个大亚基和小亚基的两个同源物，但是这些基因不是共转录的。这些基因彼此之间比以前表征的苹果酸异丙酯异构酶或高纯硝酸酶基因更相似。为了鉴定这些同源物的功能，亚单位的四种组合在大肠杆菌中异源表达，纯化并重建以产生全酶的铁硫中心。只有MJ0499和MJ1277蛋白的组合才能催化苹果酸异丙酯和柠檬酸酯的异构化反应。该对还使用柠檬酸柠檬酸酯和马来酸酯催化水合半反应。另一种广泛特异性的酶，苹果酸异丙酯脱氢酶（MJ0720）催化β-异丙基苹果酸，β-甲基苹果酸和d-苹果酸的氧化脱羧。结合这些结果，系统发育分析表明，丙酮酸通向2-氧代丁酸的途径（异亮氨酸生物合成中苏氨酸脱水酶的替代物）在细菌和古细菌中