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

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 dependen...

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Main Authors: Scott, David J., Harding, Stephen E., Winzor, Donald J.
Format: Article
Published: Elsvier 2015
Subjects:
Online Access:https://eprints.nottingham.ac.uk/42721/
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author Scott, David J.
Harding, Stephen E.
Winzor, Donald J.
author_facet Scott, David J.
Harding, Stephen E.
Winzor, Donald J.
author_sort Scott, David J.
building Nottingham Research Data Repository
collection Online Access
description 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.
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spelling nottingham-427212020-05-04T17:21:01Z https://eprints.nottingham.ac.uk/42721/ 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. 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. Elsvier 2015-12-01 Article PeerReviewed Scott, David J., 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 Diffusion coefficient; Sedimentation velocity; Ultracentrifugation http://www.sciencedirect.com/science/article/pii/S0003269715003930 doi:10.1016/j.ab.2015.08.017 doi:10.1016/j.ab.2015.08.017
spellingShingle Diffusion coefficient; Sedimentation velocity; Ultracentrifugation
Scott, David J.
Harding, Stephen E.
Winzor, Donald J.
Evaluation of diffusion coefficients by means of an approximate steady-state condition in sedimentation velocity distributions
title Evaluation of diffusion coefficients by means of an approximate steady-state condition in sedimentation velocity distributions
title_full Evaluation of diffusion coefficients by means of an approximate steady-state condition in sedimentation velocity distributions
title_fullStr Evaluation of diffusion coefficients by means of an approximate steady-state condition in sedimentation velocity distributions
title_full_unstemmed Evaluation of diffusion coefficients by means of an approximate steady-state condition in sedimentation velocity distributions
title_short Evaluation of diffusion coefficients by means of an approximate steady-state condition in sedimentation velocity distributions
title_sort evaluation of diffusion coefficients by means of an approximate steady-state condition in sedimentation velocity distributions
topic Diffusion coefficient; Sedimentation velocity; Ultracentrifugation
url https://eprints.nottingham.ac.uk/42721/
https://eprints.nottingham.ac.uk/42721/
https://eprints.nottingham.ac.uk/42721/