水性化甘化溶液的结构
Philip E Mason1, George W Neilson, John E Enderby
1Contribution from the Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA.
Journal of the American Chemical Society
|September 16, 2004
概括
化溶液显示出独特的离子-离子排序. 这种结构是通过以同位素替代和分子动力学模拟的中子衍射揭示出来的,它解释了化甘如何使蛋白质变质.
科学领域:
- 物理化学 物理化学
- 解决方案化学 解决方案化学
- 生物物理化学 生物物理化学
背景情况:
- 化甘是常见的蛋白质变质剂.
- 了解其解决方案结构是其功能的关键.
- 之前的研究缺乏对化溶液的详细结构见解.
研究的目的:
- 为了描述水性化溶液的结构.
- 为了研究离子-离子协会和水合模式.
- 为了阐明瓜尼丁化的变质能力的分子基础.
主要方法:
- 结合中子衍射与同位素替代 (NDIS) 实验.
- 进行了分子动力学 (MD) 模拟.
- 在室温下研究了3M化溶液.
主要成果:
- 模拟MD准确地复制了实验中子散射特征.
- 关尼离子呈现双模水合:有序的N-H结合和缺水的平面面.
- 观察到显著的离子离子排序,瓜尼尼离子与它们的缺水表面平行堆叠.
结论:
- 化溶液显示了丰富的离子-离子排序.
- 变质效率源于瓜尼迪尼与水和蛋白质疏水侧链相互作用的能力.
- 观察到的结构为瓜尼尼化的蛋白质变质特性提供了分子解释.
相关概念视频
Solvents
A solvent is a substance, most often a liquid, that can dissolve other substances. Here, the substance being dissolved is called a solute. When a solvent and a solute combine, they form a solution - a homogenous mixture of both the solvent and the solute. Water is a universal biological solvent. Its polar structure allows it to dissolve many other polar compounds. The ability of water to dissolve is governed by a balance between water molecules binding to each other and binding to the solute.
A...
A...
Water: A Bronsted-Lowry Acid and Base
The reaction between a Brønsted-Lowry acid and water is called acid ionization. For example, when hydrogen fluoride dissolves in water and ionizes, protons are transferred from hydrogen fluoride molecules to water molecules, yielding hydronium ions and fluoride ions:
Factors Affecting Solubility
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
Solubility
Solution, Solubility, and Solubility Equilibrium
A solution is a homogeneous mixture composed of a solvent, the major component, and a solute, the minor component. The physical state of a solution—solid, liquid, or gas—is typically the same as that of the solvent. Solute concentrations are often described with qualitative terms such as dilute (of relatively low concentration) and concentrated (of relatively high concentration).
In a solution, the solute particles (molecules, atoms, and/or ions)...
A solution is a homogeneous mixture composed of a solvent, the major component, and a solute, the minor component. The physical state of a solution—solid, liquid, or gas—is typically the same as that of the solvent. Solute concentrations are often described with qualitative terms such as dilute (of relatively low concentration) and concentrated (of relatively high concentration).
In a solution, the solute particles (molecules, atoms, and/or ions)...
Acidity and Basicity of Alcohols and Phenols
Like water, alcohols are weak acids and bases. This is attributed to the polarization of the O–H bond making the hydrogen partially positive. Moreover, the electron pairs on the oxygen atom of alcohol make it both basic and nucleophilic. Protonation of an alcohol converts hydroxide, a poor leaving group, into water—a good one. The two acid–base equilibria corresponding to ethanol are depicted below.
Aldehydes and Ketones with Water: Hydrate Formation
An oxygen-based nucleophile, like water, can undergo addition reactions with aldehydes and ketones. The reaction leads to the formation of hydrates, also referred to as 1,1-diols or geminal diols.
The formation of hydrates is a reversible reaction. Hydrate formation is influenced by steric and electronic factors accompanying the alkyl substituents on the carbonyl group: The rate of hydrate formation increases with a decrease in the number of alkyl groups attached to the carbonyl carbon. Hence,...
The formation of hydrates is a reversible reaction. Hydrate formation is influenced by steric and electronic factors accompanying the alkyl substituents on the carbonyl group: The rate of hydrate formation increases with a decrease in the number of alkyl groups attached to the carbonyl carbon. Hence,...


