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

Scott, David J.; Harding, Stephen E.; Winzor, Donald J.

Authors

DAVID SCOTT david.scott@nottingham.ac.uk
Associate Professor & Reader Inphysical Biochemistry

Donald J. Winzor



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.

Journal Article Type Article
Publication Date Dec 1, 2015
Journal Analytical Biochemistry
Print ISSN 0003-2697
Electronic ISSN 1096-0309
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 490
APA6 Citation Scott, D. J., Harding, S. E., & Winzor, D. J. (2015). Evaluation of diffusion coefficients by means of an approximate steady-state condition in sedimentation velocity distributions. Analytical Biochemistry, 490, doi:10.1016/j.ab.2015.08.017
DOI https://doi.org/10.1016/j.ab.2015.08.017
Keywords Diffusion coefficient; Sedimentation velocity; Ultracentrifugation
Publisher URL http://www.sciencedirect.com/science/article/pii/S0003269715003930
Copyright Statement Copyright information regarding this work can be found at the following address: http://eprints.nottingh.../end_user_agreement.pdf
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