TCA precipitation

[Savita Visal]

> > 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.


You can try to precipitate your protein with following protocol:

Stock solns:
0.15% deoxycholate (DOC)
72% TCA

To 1 ml of protein sample, add 0.1ml of DOC. Vortex and let it stand at RT
for 10 min

To the above add 0.1ml of 72% TCA. let it atand on ice for 30 min.

Spin the above at 17000 rpm for 30 min

Dissolve the pellet in SDS_loading buffer. If the sample is yellow (due to
TCA) add 1 µl of 250mM tris base

Voala, run the SDS_PAGE. Surely, you cannot visually see the 10µg of your
protein after TCA ppt. but after SDS_PAGE you should be able to see.
Try this protocol.

Good luck,
Savita