[RASMB] why use different loading concentration for sedimentation equilibrium

[Peter Schuck]

Hi Lin,

there's a lot of advantages of looking at the protein at a range of loading 
concentrations.  In many cases this is the only way to identify the 
stoichiometry of complexes and to determine the binding constants.  The 
general idea is that by changing the concentration you shift the population 
of the different states.
If you have a stable oligomer  (e.g. covalently linked), then you may not 
need several concentrations.  However, even in this case it is a good idea 
to check if there's any additional concentration dependent association step.

For the software, I use SEDPHAT for both sedimentation equilibrium or 
sedimentation velocity data.  You can find it with a brief description on 
how to use it at

http://www.analyticalultracentrifugation.com/sedphat/sedphat.htm

Best,
Peter Schuck


At 02:37 PM 1/13/2004 -0800, you wrote:
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>Hi,
>
>I am investigating the oligermer status of my interest protein. And I
>noticed a lot use different loading concentration at one run and
>combine the data sets and fit them. I want to know what more
>information can more than one loading concentration can give me and
>use what program to fit this group of data.
>
>
>Thanks a lot
>
>
>Lin
>
>
>
>
>
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