GST-fusion-protein

[Lang-Ming Chi]

Dear netters,
     Can anybody help me on the problem of purification of 
GST fusion protein in 6M Guanidium HCl (for solubilizing the proteins) by GST affinity column ?  
The fusion protein doesn't bind to the S-hexylglutathione-agarose (Sigma H7011).  The buffers we use are 

A) 10mM Tris base; 5mM B-ME; pH 7.0 /6M Gdm-Cl--- (binding)
B) 50mM Tris base; 5mM B-ME; 5mM Glutathione; pH 9.0
     6M Gdm-Cl                                --- (elution)

Any suggestions about changing the resin or buffers  will be
appreciated.
Thanks in advance!

Dr. Lang-Ming Chi
Ins. of Life Science
National Tsing Hua Uni.
Taiwan