Can TCA percipitate Glycoprotein? - (Apr/06/2010 )

Dera folks
Can TCA and aceton percipitate glycoprotein? The proteins including glycoproteins are in 15% sugar solution. I want to isolate the total protein.
And did anyone use the total glycoprotein isolation kit from Qiagen. Is it efficient or not. I am worried about the sugar in the solution might interfere the glycoprotein binding onto the immobilized lectin. Any suggestions?

It should work, although I don't know how would sugar behave. Add TCA to sugar solution (without protein) to see what happens.

I don't know what principle this kit is based on - if it's lectin based, sugar in solution may interfere. Kit manual should give you acceptable limits of additives in sample. Anyway, it's not a problem - you may simply dialyse your sample to remove sugar.

sugar makes the solution dense so it will be difficult to pellet the precipitate. as recommended by k.b., you should dialyze the solution.

Thank you for your replies. I tried dialyze the solution. As the protein conc. is only 20ug/ml and mostly are glycoprotein, they could bind onto semi-permeable membrane. I lost a lot. Do you think whether pretreating the membrane with tween 80 can save a little or not?

adding salt (0.15-0.2M) to the solution should prevent binding to the membrane.