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<TITLE>Re: [RASMB] Urea diffusion and sedimentation coefficient</TITLE>
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<BLOCKQUOTE>Hi Dave<BR>
<BR>
What a question! Although when you think of it, one could imagine that someone (with time on their hands) might 'in the old days' have measured the free-boundary translational diffusion coefficient (though probably not the s-value) of urea. <BR>
<BR>
One needs to bear in mind that urea can dimerise in solution, although with what Kd I do not know - though someone out there probably does (see Allan J Easteal - Can J Chem 68 1611-1615 (1990): Idrissi <U>et al</U> J Molec Liquids, 110 201-208 (2004)). The latter authors use molecular dynamics simulation to compute a value of around 1.1 e-9 m^2 sec^-1 for the self-diffusion coefficient of urea in water at 30º at 0.2 mole fraction - but this is of little use really for answering your query.<BR>
<BR>
Hope someone has some more detailed ideas than these!<BR>
<BR>
Arthur<BR>
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Arthur J Rowe<BR>
Professor of Biomolecular Technology<BR>
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University of Nottingham<BR>
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<BLOCKQUOTE><TT>Hello All<BR>
Does anyone have to hand the diffusion and sedimentation coefficient for<BR>
Urea?<BR>
cheers<BR>
<BR>
dave.<BR>
<BR>
Dr. David J. Scott<BR>
Lecturer in Physical Biochemistry<BR>
National Centre for Macromolecular Hydrodynamics<BR>
School of Biosciences<BR>
University of Nottingham<BR>
Sutton Bonington Campus<BR>
Sutton Bonington<BR>
Leicestershire<BR>
LE12 5RD<BR>
United Kingdom<BR>
dj.scott@nottingham.ac.uk<BR>
www.nottingham.ac.uk/ncmh<BR>
+44 (0) 115 951 6221 Phone<BR>
+44 (0) 115 951 6142 Fax<BR>
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