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Freezing TCA precip pellet? - (Sep/01/2005 )

Is it okay to freeze the protein pellet after TCA precipitation?
If they can be frozen, should they be frozen dry or resuspended first?

I'm doing a set of sucrose gradients, TCA/ acetone precipitating the protein from fractions, running SDS PAGE gels and then Western blotting. I'm doing both reducing and non-reducing conditions for the gels so would resuspend in the appropriate gel loading buffer.

Thanks for your help/ advice!


I am also performing sucrose gradients (5%-45%) followed by TCA precipitation. I never freeze the pellet and I don't think it is a good idea... If you need to do so, I would suggest you to freeze in a 0.32M sucrose solution.
I don't know if it is good to freeze in sample buffer, when I did that the electrophoresis was strange and I think it was due to precipitated SDS. I have good results leaving it at 4o.C for one night...
What are your sucrose gradient for? Maybe we can change some ideas about it!


its ok to freeze TCA pellets. -20 works fine for me.


during transcription assays, a colleague noticed that protein are more stable to the freeze step if frozen quick. Liquid nitrogen is a good procedure. but she have 25% glycerol in her sample.