相关实验视频
Updated: May 27, 2025
09:20
Assessing Energy Substrate Oxidation In Vitro with 14CO2 Trapping
Published on: March 23, 2022
2.0K
热力学塑造了糖溶性通路的体内酶负荷
Daven B Khana1,2, Annie Jen3, Evgenia Shishkova3,4
1Department of Bacteriology, University of Wisconsin-Madison, Madison WI USA.
bioRxiv : the preprint server for biology
|February 20, 2025
概括
热力学上不利的代谢途径需要更多的酶. 这项研究量化了细菌糖解中的酶度,揭示了热力学显著影响细胞蛋白质对代谢流量的投资.
科学领域:
- 生物化学 生物化学
- 代谢工程是代谢工程.
- 系统生物学 系统生物学
背景情况:
- 细胞代谢依赖酶来催化反应.
- 代谢反应的热力学优势影响了酶需求.
- 不同的细菌利用不同的糖解路径,具有不同的热力学特性.
研究的目的:
- 研究热力学驱动力与酶对代谢途径的投资之间的关系.
- 量化不同糖解策略的细菌中的绝对酶度和代谢流.
- 为了确定热力学约束对细胞蛋白负荷的影响.
主要方法:
- 在 *Zymomonas mobilis*, *Escherichia coli* 和 *Clostridium thermocellum* 中,量化绝对糖溶酶度.
- 酶数据与*in vivo*代谢流和吉布斯自由能量 (ΔG) 测量数据的整合.
- 对不同的糖解路径 (Entner-Doudoroff,Embden-Meyerhof-Parnas) 和发酵策略进行比较分析.
主要成果:
- 在*Z. mobilis*中非常有利的Entner-Doudoroff路径需要比*C. thermocellum*中受约束的依赖于酸盐的路径减少75%的蛋白质,以获得相应的流量.
- 在大肠杆菌中,Embden-Meyerhof-Parnas路径显示了中间的酶需求.
- 可逆的发酵途径需要比不可逆的需要更多的蛋白质来维持流量.
结论:
- 热力学驱动力是主要的 * in vivo * 在代谢途径中的酶负荷的决定因素.
- 细胞在热力学上有利的反应中投入较少的蛋白质.
- 路径可逆性和热力学有利性决定了细胞蛋白质投资策略.
相关概念视频
00:56What is Glycolysis?
163.5K
Overview
Cells make energy by breaking down macromolecules. Cellular respiration is the biochemical process that converts "food energy" (from the chemical bonds of macromolecules) into chemical energy in the form of adenosine triphosphate (ATP). The first step of this tightly regulated and intricate process is glycolysis. The word glycolysis originates from the Latin glyco (sugar) and lysis (breakdown). Glycolysis serves two main intracellular functions: generating ATP and generating...
Cells make energy by breaking down macromolecules. Cellular respiration is the biochemical process that converts "food energy" (from the chemical bonds of macromolecules) into chemical energy in the form of adenosine triphosphate (ATP). The first step of this tightly regulated and intricate process is glycolysis. The word glycolysis originates from the Latin glyco (sugar) and lysis (breakdown). Glycolysis serves two main intracellular functions: generating ATP and generating...
163.5K
01:21Glycolysis: Preparatory Phase
13.2K
In cellular metabolism (the complete breakdown of glucose to extract energy), glycolysis is the first step. Glycolysis takes place in the cytoplasm of both prokaryotic and eukaryotic cells. Glucose enters heterotrophic cells in two ways. One method is through secondary active transport, where the transport takes place against the glucose concentration gradient. The other mechanism uses a group of integral proteins called GLUT proteins, also known as glucose transporter proteins. These...
13.2K
01:25Glycolysis: Pay-off Phase
9.7K
So far, glycolysis has cost the cell two ATP molecules and produced two small, three-carbon sugar molecules. These molecules will proceed through the second half of the pathway, and sufficient energy will be extracted to pay back the two ATP molecules used as an initial investment and produce a profit for the cell of two additional ATP molecules and two even higher-energy NADH molecules.
Step 1 - 5: Glycolysis Preparatory Phase
The first phase of glycolysis has 5 steps where the glucose is...
Step 1 - 5: Glycolysis Preparatory Phase
The first phase of glycolysis has 5 steps where the glucose is...
9.7K
01:13Outcomes of Glycolysis
98.5K
Nearly all the energy used by cells comes from the bonds that make up complex organic compounds. These organic compounds are broken down into simpler molecules, such as glucose. As a result, cells extract energy from glucose over many chemical reactions—a process called cellular respiration.
Cellular respiration can occur aerobically (with oxygen) or anaerobically (without oxygen). In the presence of oxygen, cellular respiration starts with glycolysis and continues with pyruvate...
Cellular respiration can occur aerobically (with oxygen) or anaerobically (without oxygen). In the presence of oxygen, cellular respiration starts with glycolysis and continues with pyruvate...
98.5K
01:20Fates of Pyruvate
8.3K
Pyruvate is the end product of glycolysis, where glucose is oxidized to pyruvate, simultaneously reducing NAD+ to NADH. Two molecules of ATP are also produced by substrate-level phosphorylation.
In aerobic organisms, pyruvate is metabolized via the citric acid cycle to produce reduced coenzymes NADH and FADH2. These coenzymes are then oxidized in the electron transport chain to produce ATP and, in the process, regenerate the NAD+ and FAD. As seen in some cell types and organisms, fermentation...
In aerobic organisms, pyruvate is metabolized via the citric acid cycle to produce reduced coenzymes NADH and FADH2. These coenzymes are then oxidized in the electron transport chain to produce ATP and, in the process, regenerate the NAD+ and FAD. As seen in some cell types and organisms, fermentation...
8.3K
01:20Energy-requiring Steps of Glycolysis
162.9K
Glucose is the source of nearly all energy used by organisms. The first step of converting glucose into usable energy is called glycolysis. Glycolysis occurs in the cytosol of the cell over two phases: an energy-requiring phase and an energy-releasing phase. Over the first three steps, glucose is converted into different forms and attached to two phosphate groups donated by two ATP molecules, resulting in an unstable sugar. In the next two stages, the unstable sugar splits into two sugar...
162.9K