Enhanced resolution of sedimentation coefficient distribution profiles by extrapolation to infinite time.

Sedimentation velocity experiments can be used to identify two or more independent non-interacting macromolecules, which differ in their size by only a few percent. The procedure requires the extrapolation of differential apparent sedimentation coefficient distributions obtained at different running time to t --> infinity and works because it eliminates or greatly reduces diffusion effects. Here, we present an improved time extrapolation function of sedimentation distribution profiles originally presented by Stafford (In: Harding, Rowe, Horton (eds.) Analytical ultracentrifugation in biochemistry and polymer science, 1992). We describe a computing procedure with the program LAMM: to analyze concentration profiles obtained by absorbance or interference optics that utilizes suitable smoothing methods for noisy data sets and present examples which include time invariant noises.