缓冲区,pH值和温度对SPAAC反应速率的影响
Toni A Pringle1, James C Knight1,2
1School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, UK. james.knight2@newcastle.ac.uk.
Organic & biomolecular chemistry
|February 4, 2025
概括
优化应变促进的酸循环添加 (SPAAC) 反应需要仔细选择缓冲物和酸. 缓冲区类型,pH值和亚齐德结构显著影响SPAAC反应动力学,这对于生物结合策略至关重要.
科学领域:
- 生物结合化学 生物结合化学
- 化学动力学 化学动力学
- 药用化学 医学化学
背景情况:
- 应变促进的酸循环添加 (SPAAC) 是一种广泛用于生物结合的生物对等反应.
- 优化SPAAC反应条件对于高效和成功的生物结合策略至关重要.
- 诸如缓冲成分,pH值和温度等因素可以影响反应动力学.
研究的目的:
- 调查缓冲器类型,pH值和温度对SPAAC反应动力学的影响.
- 通过使用模型化物和抗体,确定SPAAC反应的最佳条件.
- 为开发改进的生物结合策略提供见解.
主要方法:
- 使用模型化物 (3-azido-L-alanine,1-azido-1-deoxy-β-D-glucopyranoside) 和硫酸DBCO-amine的SPAAC反应的动态分析.
- 反应在各种缓冲剂 (PBS,HEPES,MES,酸盐,DMEM,RPMI) 中进行,pH范围为5-10和温度为25°C和37°C.
- 使用吸收光谱测量来确定反应速率常数;还测试了DBCO修饰的抗体.
主要成果:
- 与PBS (pH7) 相比,HEPES缓冲器 (pH7) 的SPAAC反应率较高 (0.55-1.22 M-1s-1),而PBS缓冲器 (pH7) 的 (0.32-0.85 M-1s-1).
- 较高的pH值通常会增加反应速率,但在HEPES缓冲器中指出了例外情况.
- 1-azido-1-deoxy-β-D-glucopyranoside表现出比3-azido-L-alanine更快的动力学;PEG链接剂增加了31±16%的抗体结合率.
结论:
- 缓冲区选择,pH值和亚结构是优化SPAAC反应动力学的关键参数.
- HEPES缓冲器和特定的化物结构可以显著提高SPAAC反应效率.
- 结果为设计有效的生物结合协议提供了有价值的数据.
相关概念视频
Buffer Effectiveness
48.4K
Buffer solutions do not have an unlimited capacity to keep the pH relatively constant . Instead, the ability of a buffer solution to resist changes in pH relies on the presence of appreciable amounts of its conjugate weak acid-base pair. When enough strong acid or base is added to substantially lower the concentration of either member of the buffer pair, the buffering action within the solution is compromised.
The buffer capacity is the amount of acid or base that can be added to a given volume...
The buffer capacity is the amount of acid or base that can be added to a given volume...
48.4K
Calculating pH Changes in a Buffer Solution
52.6K
A buffer can prevent a sudden drop or increase in the pH of a solution after the addition of a strong acid or base up to its buffering capacity; however, such addition of a strong acid or base does result in the slight pH change of the solution. The small pH change can be calculated by determining the resulting change in the concentration of buffer components, i.e., a weak acid and its conjugate base or vice versa. The concentrations obtained using these stoichiometric calculations can be used...
52.6K
Buffers: Buffer Capacity
1.2K
Buffer capacity is the quantitative measure of a buffer to resist the change in pH. As shown in the following equation, the buffer capacity, denoted by 'beta', is expressed as the number of moles of acid or base needed to change the pH of a one-liter buffer solution by 1 unit. Here, Ca and Cb indicate the number of moles of acid and base, respectively. Note that dpH represents the change in pH.
In the graph, pH is plotted as a function of the number of moles of base (Cb) added to a weak...
In the graph, pH is plotted as a function of the number of moles of base (Cb) added to a weak...
1.2K
Buffers: Overview
3.8K
Buffers play a crucial role in stabilizing the pH of a solution by mitigating the effects of small amounts of added acid or base. They consist of a weak acid and its conjugate base or a weak base and its conjugate acid. A solution of acetic acid and sodium acetate is an example of a buffer that consists of a weak acid and its salt: CH3COOH (aq) + CH3COONa (aq). An example of a buffer that consists of a weak base and its salt is a solution of ammonia and ammonium chloride: NH3 (aq) + NH4Cl (aq).
3.8K
Titration of a Weak Acid with a Strong Base
2.1K
In titrating a weak acid with a strong base, different calculation methods are applied at various stages. Initially, the pH of a weak acid like acetic acid is calculated using its dissociation constant (Ka) and an ICE table. Upon addition of a strong base such as sodium hydroxide, a buffer forms, and its pH is determined using the Henderson-Hasselbalch equation. As more base is added and the titration reaches the halfway point, the pH becomes equal to the pKa of the acid, indicating equal...
2.1K
Measuring Reaction Rates
24.3K
Polarimetry finds application in chemical kinetics to measure the concentration and reaction kinetics of optically active substances during a chemical reaction. Optically active substances have the capability of rotating the plane of polarization of linearly polarized light passing through them—a feature called optical rotation. Optical activity is attributed to the molecular structure of substances. Normal monochromatic light is unpolarized and possesses oscillations of the electrical...
24.3K


