I have seen this when expressing sub-domains of a larger protein.
Adding some (about 0.5% w/v) BOG (beta octylglucoside) worked well for
cases similar to what you've described.
Cheers,
Quyen
_______________________________
Quyen Hoang, Ph.D
Department of Biochemistry and Molecular Biology,
Stark Neurosciences Research Institute
Indiana University School of Medicine
635 Barnhill Drive, Room MS0013D
Indianapolis, Indiana 46202-5122
Phone: 317-274-4371
Fax: 317-274-4686
email: [email protected]
On Jan 8, 2010, at 7:41 AM, Sivaraman Padavattan wrote:
Dear all,
I am trying to express the human protein using bacterial expression
strain (Rosetta) and purified using Ni-NTA affinity purification.
The Molecular weight of out protein is 47 kDa. In SDS-PAGE, we have
seen that 27 kDa contaminant protein co-eluted with our protein even
at high concentration of Imidazole. In Superose 12 column, these two
proteins eluted as a single peak and its corresponding molecular
weight suggestive of partial interaction. By mass mapping we have
found 27 kDa band is an adenylate kinase. Is there any specific way
to separate adenylate kinase from our protein?
Thanks in advance,
Sivaraman Padavattan
