Can GST-tag be separated from GST-fusion protein - (Oct/19/2009 )

Dear all,

We need to express and purify a protein with some kind of tag. The most convenient one to us is GST. However, we always get 2 main bands after the affinity column - the GST-fused protein and the GST itself. Since we don't want to cut the tag out this time, we need to purify the GST-fused protein from the GST tag and cannot use the affinity column again.

I know GST will form dimer. Don't know if GST will form dimer with GST-fused protein too? If so, it will be very hard to purify my GST-fused protein from GST.

Anyone has encouter this situation before?

Thanks.

Nest

am trying digestion without glutathione. will tell u if it works though in our lab, separation of the two proteins has been done before