seeking TCA precipitation advice - (Mar/01/2008 )

My TCA precipitation stinks! Even with the addition of a few micrograms of carrier protein, I seem to be losing substantial portion of the input protein contents after precipitation and washes. The pellet is hardly visible.
Any advice? Thanks.

Dear Name
I understand that you have started with very less protein, why dont you start once with higher concentrations and check what is the problem. Use ice cold TCA and keep it for 1/2 hr incubation on ice after adding TCA. at this step only you have to get some white ppt , if it formed go for acetone wash otherwise you wont get any ppt after wash.

correct me if iam wrong
waiting for ur reply

Hi shan,
Due to the nature of this particular experiment, I can not increase the concentration that much (~500ng/ml), except that I can add carrier proteins extraneously. The TCA is cold and I do precipitation in the firdge overnight.
I usually do see pellet and some proteins do get recovered after precipitation/wash, but the recovery efficiency seems to be less than 50%.