[RASMB] Urea diffusion and sedimentation coefficient (further)

[Doug Barrick]

Greetings,

Regarding the strength of the urea dimer,  John Schellman measured  
the equilibrium constant
for urea dimerization in aqueous solution, and I believe the  
reference is

Schellman JA. The thermodynamics of urea solutions and the heat
of formation of the peptide hydrogen bond. Compt-Rend Lab
Carlsberg, Ser Chim 29:223–229 (1955).

Hope this helps,

Doug Barrick

Professor of Biophysics
T.C. Jenkins Department of Biophysics
Johns Hopkins University
3400 N. Charles St.
Baltimore MD 21218
TEL (410) 516-0409
FAX (410) 516-4118




On Aug 8, 2007, at 10:15 AM, Arthur Rowe wrote:

> Greetings everyone
>
> (and especially those interested in the rather obscure topic of the  
> diffusion coefficient of urea)
>
> Further to my earlier mail (below), two further things to be added:
>
> (1) I am much indebted to Dr Trushar Patel for mailing me a  
> reference to a paper from a more 'classical' age which gives values  
> for the diffusion coefficient of urea (and a range of other  
> solutes) at temperatures from 1º to 37º :
>
> L G Longsworth (1954) "Temperature dependence of diffusion in  
> aqueous solutions" J Phys Chem 58 770-773
>
>
> (2) I have found a very recent publication (June 2007) which  
> explores the issue by molecular dynamics, and comes to the  
> conclusion that at the urea levels commonly used for protein  
> denaturation, urea is about 20% is dimeric:
>
> Stump & Grubmüller (2007) J Phys Chem B 111 6220-6228
>
> Arthur
>
>
> --
> *******************************************************
> Arthur J Rowe
> Professor of Biomolecular Technology
> NCMH Business Centre
> University of Nottingham
> School of Biosciences
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>
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> *******************************************************
>
>
>
>
>
> Hello All
> Does anyone have to hand the diffusion and sedimentation  
> coefficient for
> Urea?
> cheers
>
> dave.
>
> Dr. David J. Scott
> Lecturer in Physical Biochemistry
> National Centre for Macromolecular Hydrodynamics
> School of Biosciences
> University of Nottingham
> Sutton Bonington Campus
> Sutton Bonington
> Leicestershire
> LE12 5RD
> United Kingdom
> dj.scott at nottingham.ac.uk
> www.nottingham.ac.uk/ncmh
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