Removal of CTAB (cationic detergent) from proteins

rdudley at rdudley at
Tue Jun 23 11:04:48 EST 1998

In article < at>,
  s970856 at CUHK.EDU.HK (tonyho) wrote:
> Hi, everybody
> Does anyone know how to remove CTAB (cetyltrimethylammonium bromide - a
> cationic detergent) from protein sample? My desired protein in the cells is
> cationic, hence requiring CTAB (0.3% in normal saline) to lyse the cells &
> granules for release of the protein. Also CTAB acts as a surfactant to
> prevent non-specific binding of my cationic protein to the inner surface of
> container.
> CTAB itself can react with Coomassie Blue in the Bradford protein assay to
> give an over-estimation of total protein concentration. Does anybody know
> how to solve this problem?
> Thanks a lot if u can solve my headache problems
> Tony Ho (Ph. D student from CUHK)


I'm not sure if this will do the trick or not, but look at Bio-Rad's web site
(  They have a Biogel or something like that specifically
for removing detergents.  You might also investigate hydrophobic interaction
chromatography, or possibly precipitate a sample of the protein and read
that. Or try BCA assay?  You can find info about precipitation in the
archives of this newsgroup at


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