Procedures for Analytical Ultracentrifugation

超离心分析方法 当大分子存在于溶液中时，超离心力提供了关于大分子的分子量和相互作用的直接和可靠的信息。沉降平衡方法是基于平衡热力学，因此可以提供可靠的估计参数的分子在溶液中。对浓度分布的干涉观测为这种估计提供了高度的精确度。最近在现代超精密仪器中引入的自动化干涉测量法为研究大分子分布提供了一种具有高“信噪比”的强有力工具。拟议的研究将探讨如何提高这种测量的精度。这将导致能够在更广泛的条件下进行实验，并更好地区分平衡和速度实验所研究的系统的替代解释（模型）。 平衡沉降实验的软件和新方法如果成功，将使实验更容易进行，更快或更精确，从而能够提供更有意义的信息。例如，这些改进将有助于确定蛋白质制剂中的杂质水平或估计分子之间相互作用的强度。待开发的程序应该使从困难的相互作用系统（例如细胞因子及其受体之间形成的复合物）中获得信息变得更容易（有时甚至可能）。这些系统通常表现出一系列复杂的形成，难以确定化学计量。 这些不同的方法将被应用到热门的问题，主要是，但不完全是，从生物技术企业试图回答有趣的问题。

Procedures for Analytical Ultracentrifugation The ultracentrifuge provides direct and reliable information about the molecular weights and the interactions of macromolecules as they exist in solution. Sedimentation equilibrium approaches are based on equilibrium thermodynamics and thus can provide reliable estimates of the parameters of molecules in solution. Interferometric observations of concentration distributions provide a high degree of precision for such estimations. The recent commercial introduction of automated interferometry in a modern ultracentrifuge provides a powerful tool with a high "signal to noise ratio" for studying macromolecular distributions. The proposed research will examine ways to improve the precision of such measurements. This should lead to the ability to carry out experiments under a wider range of conditions and to better distinguish amongst alternative explanations (models) of the systems investigated both for equilibrium and velocity experiments. Software and new approaches to equilibrium sedimentation experiments, if successful, will make experiments easier to carry out, and either faster or more precise and thus able to provide more meaningful information. These improvements would, for example, facilitate determinations of levels of impurities in protein preparations or estimations of the strength of interactions between molecules. The programs to be developed should make it easier (and sometimes possible) to obtain information from difficult interacting systems, such as the complexes formed between cytokines and their receptors. These systems often exhibit a sequence of complex formations where it is difficult to determine stoichiometries. These various approaches will be applied to problems of topical interest, largely, but not completely, from biotechnology enterprises to try to answer interesting questions.