TCA-precipitation?

larson eric elarson at ux1.cso.uiuc.edu
Wed Jan 11 09:17:32 EST 1995


J.Marcus at tpp.uq.oz.au (John Marcus) writes:

>>I am looking for good method to precipitate a highly purified protein
>>before 
>>analysing it on a SDS-PAGE.
>>The fraction has about 1M KCl and should be concentrated from 500 ul to
>>about 20.
>>
>>Thanks for suggestions
>>
>>PIT
>>
>Have you thought about using a Centricon or Microcon centrifugal
>filtration device.  Essentially, you put your protein sample into
>the microcon (~500ul capacity) and then spin in a microcentrifuge
>for 1 min to 30 min (depending on the molecular weight cutoff of 
>the filter that you are using at the time).  I think Amicon may 
>have molecular weight cuttoffs as low as 1000Da.  When you are done 
>spinning you should be left with about 10ul volume if you use a
>microcon; although, this holdup volume is not very predictable.  
============
 
An excellent suggestion, especially since the KCl will have to be removed
or reduced to prevent precipitation of the SDS.

-- 
Eric Larson                  | University of Illinois at Urbana-Champaign
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