Kyle Coachman/Linda Warfield/Steve Hahn

Last modified 5/13/02

To concentrate proteins for analysis by SDS PAGE:

If a small amount of protein is to be precipitated (less than a few micrograms), add Insulin as a carrier protein (10 micrograms of Sigma insulin, I-5500, per sample works well).

1. Add an equal volume of 20% TCA (trichloroacetic acid) to protein sample.
2. Incubate 30 min on ice.
3. Spin in microfuge at 4 deg. For 15 min.
4. Carefully remove all supernatant.
5. Add ~300 ul cold acetone and spin 5 min at 4 degrees.
6. Remove supernatant and dry pellet.
7. Resuspend samples in SDS PAGE loading buffer. Load to SDS PAGE after heating at 65 deg for 3 min.