TCA precipitation

[Mick Partis]

poseva at iata.csic.es (Eva Dupille) wrote:
>Hello,
>I have a protein problem precipitation. I did a TCA precipitation, 15 % 
>for 1 h at 4 C, and I got, nothing at all.
>Sure that I have proteins, I get enzyme activity and with biorad, before 
>precipitation, I have around 10 micrograms/ml.
>Is it a problem of temperature or incubation time ??
>Please, if you have some comments, let me know. That s boring to lose so 
>many time in protein purification, to lose all the samples for a protein 
>precipitation problem ..
>Thanks in advance, sorry for the approximative english.
>Eve

You don't say why you want to precipitate your protein:  if you are 
running assays and just want to get rid of the protein then 15% TCA 
should inactivate.  If you need a precipitate then why not add a carrier 
protein?  Adding some serum albumin (or any cheap, pure protein) at about 
1 mg/ml before adding your TCA and your protein should co-precipitate.  
If you are precpitating prior to running SDS-PAGE, just make sure the MW 
of the carrier protein is different from that of your protein.

Mick
-- 
mick.partis at hri.ac.uk         Horticulture Research International
http://www.geocities.com/CapeCanaveral/1957/