[Protein-analysis] Re: problem of concentrating protein

sandy_zhu_2006 from hotmail.com via proteins%40net.bio.net (by sandy_zhu_2006 from hotmail.com)
Sat Jan 19 07:29:04 EST 2008


On 1=D4=C217=C8=D5, =C9=CF=CE=E73=CA=B118=B7=D6, "Dr Engelbert Buxbaum"
<engelbert_buxb... from hotmail.com> wrote:
> Am 10.01.2008, 01:01 Uhr, schrieb <sandy_zhu_2... from hotmail.com>:
>
> >     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.
>
> What is the composition of your elution buffer? Does it contain Zn? Does  =

> the precipitation also occur when the binding buffer does not contain Zn?

My elution buffer do have Zn(1mM ZnCl2) in it.How to improve its
solubleness
 is the mayor concern right now.


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