...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Crystal growth & design >Lysozyme Self-Association in Aqueous NaCl at pH 4.0 and 20 ℃
【24h】

Lysozyme Self-Association in Aqueous NaCl at pH 4.0 and 20 ℃

机译：pH 4.0和20℃NaCl水溶液中的溶菌酶自缔合

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The rate of membrane permeation of molecules of the protein, lysozyme, dissolved in aqueous crystallization media depends on the square root of the ionic strength. This dependence can be explained by assuming that there is an equilibrium between lysozyme monomers and dimers. Using electrolyte theory and the hypothesis that the dimerization equilibrium involves exchange of H~+ with the buffer, we calculate that a dimer in aqueous NaCl buffered to pH 4.0 at 20 ℃ has a charge equal to +18.6 |e|, where e is the electron charge. We find further that the standard free energy of formation of the dimer from monomers is 173 kJ mol~(-1), while the equilibrium constant for dimer formation is 1.2 * 10~(-31). Although these values imply that dimers are not prevelant under standard conditions, we find that the mass action effects of H~+ exchange with the buffer and the stabilizing effects of the net electrostatic interaction of both monomers and dimers with Na~+ and Cl~- ions enhances the presence of dimers under the conditions ordinarily encountered in crystal growth experiments. This information is of importance in understanding the mechanism of lysozyme crystallization, because the formation of dimers is usually considered as the first step in the nucleation process that presumably precedes the appearance of the crystals.
机译：溶解在水性结晶介质中的蛋白质（溶菌酶）分子的膜渗透速率取决于离子强度的平方根。可以通过假设溶菌酶单体和二聚体之间存在平衡来解释这种依赖性。使用电解质理论和关于二聚平衡涉及与缓冲液交换H〜+的假设，我们计算出在20℃缓冲到pH 4.0的NaCl水溶液中的二聚体具有等于+18.6 | e |的电荷，其中e是电子电荷。我们进一步发现，由单体形成二聚体的标准自由能为173 kJ mol〜（-1），而形成二聚体的平衡常数为1.2 * 10〜（-31）。尽管这些值表明二聚体在标准条件下并不优越，但我们发现H〜+与缓冲液交换的质量作用效应以及单体和二聚体与Na〜+和Cl〜-的净静电相互作用的稳定作用。在晶体生长实验中通常遇到的条件下，离子增加了二聚体的存在。该信息对于理解溶菌酶结晶的机理很重要，因为通常认为二聚体的形成是成核过程的第一步，大概是在晶体出现之前。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号