larson eric elarson at
Wed Jan 11 09:17:32 EST 1995

J.Marcus at (John Marcus) writes:

>>I am looking for good method to precipitate a highly purified protein
>>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
>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
USDA/Agronomy                | 190 PABL; 1201 W. Gregory; Urbana, IL 61801
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Fidonet: 1:233/4.1           | My opinions are my own, but correct :-) 

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