Evaluation of diffusion coefficients by means of an approximate steady-state condition in sedimentation velocity distributions

Scott, David J. and Harding, Stephen E. and Winzor, Donald J. (2015) Evaluation of diffusion coefficients by means of an approximate steady-state condition in sedimentation velocity distributions. Analytical Biochemistry, 490 . pp. 20-25. ISSN 1096-0309

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Abstract

This investigation examined the feasibility of manipulating the rotor speed in sedimentation velocity experiments to spontaneously generate an approximate steady-state condition where the extent of diffusional spreading is matched exactly by the boundary sharpening arising from negative s–c dependence. Simulated sedimentation velocity distributions based on the sedimentation characteristics for a purified mucin preparation were used to illustrate a simple procedure for determining the diffusion coefficient from such steady-state distributions in situations where the concentration dependence of the sedimentation coefficient, s = s0/(1 + Kc), was quantified in terms of the limiting sedimentation coefficient as c → 0 (s0) and the concentration coefficient (K). Those simulations established that spontaneous generation of the approximate steady state could well be a feature of sedimentation velocity distributions for many unstructured polymer systems because the requirement that Kcoω2s0/D be between 46 and 183 cm−2 is not unduly restrictive. Although spontaneous generation of the approximate steady state is also a theoretical prediction for structured macromolecular solutes exhibiting linear concentration dependence of the sedimentation coefficient, s = s0(1 − kc), the required value of k is far too large for any practical advantage to be taken of this approach with globular proteins.

Item Type: Article
Keywords: Diffusion coefficient; Sedimentation velocity; Ultracentrifugation
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Biosciences
Identification Number: 10.1016/j.ab.2015.08.017
Depositing User: Eprints, Support
Date Deposited: 10 May 2017 13:41
Last Modified: 11 May 2017 10:28
URI: http://eprints.nottingham.ac.uk/id/eprint/42721

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