The protein I am purifying is a kind of zinc finger protein which
has 81 amino acid and its theoretical pI is 9.19.But after purified
with Hitrap Heparin column the target protein were still stable,then
when I use the binding buffer(20mM Tris,10mM Mer,100mM NaCl and 1mM
ZnCl2,pH 7.0)to dialyze in order to remove the 2M NaCl which were used
in eluting the protein from the Heparin column, I found that there are
many sediment in it.
How to solve this problem?Is there any buffer which is more siutable
than Tris? Since at pH7.0 Tris is not as efficient as it was.
Plus I tried phosphate buffer,but it will interact with the ion
zinc (within zinc finger protein) and produce sendiment too.