TCA protein precipitation

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 ~300μl 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.