Alternative strategies for the characterization of associations in multicomponent solutions via measurement of sedimentation equilibrium.

Four strategies for the analysis of sedimentation equilibrium of solutions containing two solute components in the context of models for equilibrium association are described:(1)Direct modeling of the equilibrium gradients of a single experimentally measurable signal measured in each of several samples of differing composition;(2)Direct modeling of the equilibrium gradients of two (or more) signals measured in each of several samples of differing composition;(3)Calculation of the independent component concentration gradients in individual samples via analysis of the gradients of two or more signals in the sample, followed by modeling of the component concentration gradients from several samples of differing composition; and(4)Calculation of the signal-average buoyant molar mass as a function of solution composition, followed by modeling of the composition dependence of the signal-average buoyant molar mass in the context of an association model. Examples of the application of each strategy are presented and compared, and conclusions are drawn regarding the relative utility of each method for different types of experiments and systems studied. [ABSTRACT FROM AUTHOR]