In article <AQ2V9.1555$i73.314446 at twister.neo.rr.com>, "Artem Evdokimov" <AEVDOKIMOZ at cinci.rr.com> wrote:
>"Debashis Mukhopadhyay" <debmukh at scripps.edu> wrote in message
>news:Pine.SGI.4.20.0301141518540.199543-100000 at signal.scripps.edu...>> Hi,
>>>> I am using Ni affinity column to isolate my protein which came out
>> successfully with Imidazole. However, I found a lot (~100 mg) of protein
>> still sticking to the column and I eluted them out by stripping off the
>> Ni+2 from the column using EDTA. So, this solution now contains my protein
>> + (may be some contaminant) + Ni and EDTA and is colored blue (as
>> expected). At this point I wonder if there is any way / standard practice
>> to separate the protein from Ni+2, so that I can re-utilize it.
>>>> Any help would be appreciated.
>>>> Regards,
>> Deb
>>It's not very likely that the protein would be OK. In my experience, strange
>things happen to proteins exposed to soluble nickel salts, and Ni tends to
>persist even after thorough cleanup.
Sounds strange. One would think that EDTA is in large excess and
since it binds Ni with Ka > 10e13 there would be no Ni bound to
protein.
>You can try, however - simple desalting
>(size-exclusion) should do the job. After desalting, remaining nickel can be
>sometimes scavenged using chelating resins.
If the volume is large, simple dialysis should do the job too.
To be on a safe side, I'd dialyse first against 1 mM EDTA
(with a change) and only after that in whatever other buffer
that suits me.
DK
