can you elute off the column with low pH ? Or EDTA if you don't want imidazole around ?
Jürgen On Jul 14, 2013, at 10:29 AM, Raji Edayathumangalam wrote: Thanks everyone for your responses. I definitely plan to save the flowthrough so we'll see what happens. My protein has a His tag and I did consider doing an affinity step for concentration except I do not want to have imidazole for some functional assays that I need to carry out with the protein. Just occurred to me that I could simply dialyze out the imidazole after the affinity step. Thanks again! Raji On Sat, Jul 13, 2013 at 8:47 PM, Raji Edayathumangalam <r...@brandeis.edu<mailto:r...@brandeis.edu>> wrote: Hi Folks, Sorry for the non-ccp4 post. I have purified an 18kDa membrane protein and want to concentrate the protein from gel filtration fractions, which are in buffer containing 0.05% DDM (well above the CMC for DDM). My colleague was able to concentrate a 30kDa membrane protein using a 100kDa MWCO concentrator but I am not sure if I can do the same without losing protein in the flowthrough. On the other hand, if use too low a MWCO for the concentrator, then I'm concerned that I may end up concentrating the DDM and end up with too much detergent in the final sample. Any tips about how to concentrate my low MW protein without concentrating the DDM? Many thanks. Raji -- Raji Edayathumangalam Instructor in Neurology, Harvard Medical School Research Associate, Brigham and Women's Hospital Visiting Research Scholar, Brandeis University -- Raji Edayathumangalam Instructor in Neurology, Harvard Medical School Research Associate, Brigham and Women's Hospital Visiting Research Scholar, Brandeis University ...................... Jürgen Bosch Johns Hopkins University Bloomberg School of Public Health Department of Biochemistry & Molecular Biology Johns Hopkins Malaria Research Institute 615 North Wolfe Street, W8708 Baltimore, MD 21205 Office: +1-410-614-4742 Lab: +1-410-614-4894 Fax: +1-410-955-2926 http://lupo.jhsph.edu
