乙-CoA合成酶的动力机制:在可变的Co/Co2压力下稳定状态合成
E L Maynard1, C Sewell, P A Lindahl
1Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
Journal of the American Chemical Society
|July 18, 2001
概括
这项研究揭示了一氧化碳 (CO) 和二氧化碳 (CO2) 如何与来自Clostridium thermoaceticum的乙烯基-CoA合成酶 (ACS) 相互作用. 高度的二氧化碳抑制了ACS活动,而二氧化碳和二氧化碳在复杂的催化机制中充当了基质.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 微生物的新陈代谢
背景情况:
- 来自Clostridium thermoaceticum的乙-CoA合成酶 (ACS) 对于碳固定通路至关重要.
- 了解ACS与一氧化碳 (CO) 和二氧化碳 (CO2) 等气态基质的动态行为,对于阐明其催化机制至关重要.
研究的目的:
- 为了研究由Clostridium thermoaceticum ACS.催化的乙-CoA合成的稳定状态动力学.
- 为了确定CO和CO2的不同部分压力对酶活性的影响.
- 根据实验动力学数据提出一个可信的催化机制.
主要方法:
- 在不同度的CO和CO2下测量乙-CoA合成的初始反应速率.
- 分析酶动力学以确定Vmax和基质抑制等参数.
- 评估11个候选反应机制,以确定最简单的模型适合数据.
主要成果:
- 酶活性最初随着CO度的增加而增加,然后在较高的CO度下急剧下降,表明基质抑制.
- 二氧化碳表现出类似的抑制行为,两种气体都充当竞争的基质.
- 提出了一种涉及多个CO分子与不同酶形式的合作结合的机制,以解释抑制和残留活性.
结论:
- 该研究阐明了乙-CoA合成酶的复杂动力机制,涉及CO和CO2的激活和抑制.
- 二氧化碳和二氧化碳都充当了基质,竞争的是相同的酶形式.
- CO的合作结合导致酶抑制,其余活性归因于特定的酶状态.
相关概念视频
Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
ATP Synthase: Mechanism
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased ATP...
Introduction to Mechanisms of Enzyme Catalysis
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes a mild...
Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Introduction to Mechanisms of Enzyme Catalysis
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes a mild...
Biosynthesis in Bacteria
Biosynthesis in bacteria is a fundamental anabolic process that generates essential macromolecules, including proteins, nucleic acids, lipids, and polysaccharides. These macromolecules are critical for cellular growth, replication, and function. The process is tightly regulated and energetically linked to catabolic pathways to ensure optimal resource utilization.Biosynthetic pathways begin with precursor metabolites such as pyruvate, acetyl-CoA, and glucose-6-phosphate derived from glycolysis,...


