Purification of GST-fusion protein

Artem Evdokimov AEVDOKIMOZ at cinci.rr.com
Tue Apr 30 20:18:01 EST 2002

1) cutting on column often does not work. Cleavage in solution is generally
a safer alternative. Make sure that cleavage actually HAPPENS in solution
before going to column cleavage - you may discover that steric reasons
prevent efficient cleavage in your particular case.
2) proteins often stick to glutathione columns nonspecifically (use reducing
agent + detergent to try and wash them off)
3) try different protease sites (yes that means re-cloning, but that's only
a few days' worth of time these days)  (your thrombin may have become
inactivated, there's several possible reasons for that)
4) use a different tag :)


"Chan Shzu Wei" <mdccsw at nus.edu.sg> wrote in message
news:BCED9767330536479E416EFC52D3F9B9038E990B at pfs01.ex.nus.edu.sg...
> Dear colleagues,
> I have problem in purifying my protein of interest  from the GST from
> using GST column. I have cut my protein of interest (~25.7kDa) from the
> GST fusion protein (26 kDa) with thrombin protease, and as in theory, I
> should get my protein of interest in flow through, but it didn't. I
> found that it came out together with the GST when I eluted with the GST
> elution buffer. Please give some suggestion to purify my protein of
> interest from the GST protein. Thanks.
> Joyce

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