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Concentration dependence of translational diffusion coefficients for globular proteins

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 examines published results of traditional diffusion experiments on ovalbumin and bovine serum albumin to determine the extent to which assumed concentration independence of the translational diffusion coefficient is a reasonable approximation in the analysis of boundary spreading in sedimentation velocity experiments on proteins. Although significant positive concentration dependence of the diffusion coefficient (D) for both proteins is predicted by current theories, none has been detected in these experimental diffusion studies performed under the constraints of constant temperature and solvent chemical potential (those also pertinent to sedimentation velocity). Instead, the results are better described by the relatively minor concentration dependence predicted by considering solution viscosity to be an additional source of D–c dependence. Inasmuch as the predicted variation in D for solutions with concentrations below 10 mg mL-1 is within the uncertainty of experimental estimates, these findings support use of the approximate solution of the Lamm equation developed by Fujita for the quantitative analysis of boundary spreading in sedimentation velocity experiments on proteins.

Journal Article Type Article
Publication Date Dec 7, 2014
Journal Analyst
Print ISSN 0003-2654
Electronic ISSN 1364-5528
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 139
Issue 23
APA6 Citation Scott, D. J., Harding, S. E., & Winzor, D. J. (2014). Concentration dependence of translational diffusion coefficients for globular proteins. Analyst, 139(23), doi:10.1039/c4an01060d
DOI https://doi.org/10.1039/c4an01060d
Publisher URL http://pubs.rsc.org/en/journals/journalissues/an#!issueid=an139023&type=current&issnprint=0003-2654
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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