通过丁氧化酶的氧化反应:对反应机制的理论研究
Tatsuo Amano1, Noriaki Ochi, Hirofumi Sato
1Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan.
Journal of the American Chemical Society
|June 15, 2007
概括
丁氧化酶 (XO) 使用含有的活性部位进行氧化. 提出了一种新的去质子化机制,显示出一种更稳定的产品,与实验数据一致,使其成为最合理的途径.
科学领域:
- 生物化学 生物化学
- 计算化学的计算化学
- 酶学 是一种酶学.
背景情况:
- 丁氧化酶 (XO) 是一种含有的酶,对代谢至关重要.
- 了解其氧化机制是理解细胞过程的关键.
研究的目的:
- 为了理论上研究丁氧化酶的氧化机制.
- 为了比较拟议的反应途径,包括最近提出的去质子化机制.
- 为了确定XO介导氧化反应的最合理的反应机制.
主要方法:
- 使用XO活性部位的模型复合体进行理论研究.
- 形式胺氧化的计算分析,一个基准基板.
- 协调,阶段性和去质子化启动机制的系统比较.
主要成果:
- 之前提出的协调和分阶段机制显示适度的激活障碍,但不稳定的产品,与实验数据不一致.
- 一个新研究的去质子化启动机制显示了适度的激活屏障和高的外热性.
- 脱机制的产物与实验同位素结果保持一致,而对于具有脱活性位点的阶段性机制,中间优化失败了.
结论:
- 活性部位的脱发生时具有相当大的外热性.
- 一步式去质子化机制是最合理的路径,用于丁氧化酶介导的氧化.
- 这一发现使理论模型与XO催化中的实验观测相协调.
相关概念视频
Oxidation of Alcohols
In this lesson, the oxidation of alcohols is discussed in depth. The various reagents used for oxidation of primary and secondary alcohols are detailed, and their mechanism of action is provided.
The process of oxidation in a chemical reaction is observed in any of the three forms:
The process of oxidation in a chemical reaction is observed in any of the three forms:
Oxidation of Phenols to Quinones
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
Rate-Determining Steps
Relating Reaction Mechanisms
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
Radical Autoxidation
The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...
Phase I Oxidative Reactions: Overview
Phase I biotransformation, or functionalization, is a crucial chemical process that converts drugs and other xenobiotics into more water-soluble forms, facilitating expulsion from the body. It involves oxidative, reductive, and hydrolytic reactions that add or unveil polar functional groups on lipophilic substrates. Key players in phase I reactions are the mixed-function oxidases. Situated in liver cell microsomes, these enzymes predominantly carry out drug metabolism. They require molecular...
Redox Reactions
Oxidation-reduction or redox reactions involve the transfer of electrons from one molecule or atom to another. When an atom gains an electron, another atom must lose an electron, meaning oxidation and reduction must occur together. Since the redox occurs in pairs, the atom that gets oxidized is also called the reducing agent or reductant, and the atom that is reduced is also called the oxidizing agent or oxidant. A straightforward way to remember the definitions of oxidation and reduction is...


