[RASMB] proteins in water

[Arthur Rowe]

Dear Carlos

Can I just add one note to the clear expositions on this issue already contributed? Peter Budd's article on sedimentation of polyelectrolytes (in "Analytical Ultracentrifugation in Biochemistry & Polymer Science" eds. S E Harding, J C Horton & A J Rowe), The Royal Society of Chemistry, London) makes it depressingly clear that in pure water - as compared to very dilute salt solution - there is no simple extrapolation to infinite dilution available. 

Best of luck with your system!

Arthur


On 23 Jul 2012, at 08:47, Carlos Alfonso Botello wrote:

> Thank you very much for all your helpful answers. 
> 
> 
> Carlos
> 
> 
> 
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> Dear colleagues,
> 
> We are running a 10 kDa protein at concentrations 0.2-2 mg/ml in water (no buffer is present).The sedimentation coefficients that we are obtaining are lower than expected for the monomer (1.4 - 1.5S). Is there any correction of the S that we could apply to obtain the correct S20,W.
> 
> Thank you in advance for your help,
> 
> Carlos
> 
> 
> Dr. Carlos Alfonso
> Departamento Biologia Celular y Molecular
> Laboratorio de Interacciones Macromoleculares: Bioquímica Citomimética
> Centro de Investigaciones Biológicas, CSIC
> C/ Ramiro de Maeztu, 9. 
> 28040-MADRID
> Tlfno.- 91 8373112 ext.4406-4408-4297 
> Fax: 915360432.
> E-mail: carlosa at cib.csic.es
> NEW lab web page: 
> http://www.cib.csic.es/es/grupo.php?idgrupo=49
> P Antes de imprimir este mensaje piense bien si es necesario hacerlo. El medioambiente es cosa de todos. 
> Please consider your environmental resposability before printing this e-mail.
> 
> 
> 
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Professor Arthur J Rowe
NCMH/Food Sciences
University of Nottingham
Sutton Bonington
Leics LE12 5RD UK

Tel: +44 115 9516156
arthur.rowe at nottingham.ac.uk



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