In article <3euc3i$3ib at sunserver.lrz-muenchen.de>, u7q11aa at sunmail.lrz-muenchen.de (Peter Alliger) says:
>>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.
Alternatively, you could desalt your sample with the microcon;
recover it and then proceed to dry your sample with a stream of
nitrogen or else a speedi-vac hooked up to a vacuum pump.
I hope that is helpful.
Regards,
John Marcus
