GST fusion protein degradation - (Jul/31/2004 )

The Gst-fusion protein which I expressed in e. coli seems to degrade very quickly even at 4C or at -20 C or cleave from the Gst . This happens even after adding PMSF and protease inhibitors in the washes and even when the protein is bound to beads. could you tell me how to store the protein for a time period atleast up to six months woithout facing this problem.
thank you

You could freeze it in aliquotes in the -80 C.

ALthough it is a pain, you could clean it up on a gel filtration column to decrease the concentration of contaminating proteases. Alternatively use a broad-spectrum inhibitor such as the mini-protease tablets that are widely available..