CTAB and Membrane Protein Purification

[Federici]

In article (Dans l'article) <3187492D.3FDC at igmors.u-psud.fr>, Mark Blight
<BLIGHT at igmors.u-psud.fr> wrote (écrivait) :

> Hi,
> 
> Does anyone have any experience with CTAB as a detergent for membrane =
> 
> protein purification?
> 
>  I recently checked a range of detergents for the solubilisation of an =
> 
> E.coli integral inner membrane protein and CTAB was on the shelf (we use =
> 
> if for DNA preps' usually). Since CTAB is a close relative of CDAB =
> 
> (Cetyldimethylethyl ammonium bromide) which is a cationic detergent, I =
> 
> tried it out.
> 
> To my great suprise CTAB worked extremely well and efficiently =
> 
> solubilizes my membrane protein out of the cell envelope. Out of 10 =
> 
> detergents tried only Triton-X100, IGEPAL and CTAB worked.
> 
> I would be very interested in any comments upon the use of CTAB for =
> 
> membrane protein (or just "protein") purification.
> 
> Thanks,
> 
>                                                                         Mark.
> ____________________________________________
> 
>                         M. Blight, =
> 
>                         Institut de G=E9n=E9tique et Microbiologie,
>                         B=E2timent 409,
>    Universit=E9 de Paris XI,
>    91405 Orsay cedex
>    FRANCE.
>         =
> 
>    Tel: (+33 1) 69 41 66 99
>                         Fax: (+33 1) 69 41 78 08
>    e-mail:      blight at igmors.u-psud.fr
> ____________________________________________

For E.coli proteins to be purified, DNA must be eliminated; (nucleic acids
represent 7% of the wet weight or 23,6% of dry weight of cells). CTAB is
used in this purpose. The final content of CTAB is determined by: nucleic
acids/CTAB=1 (W/W).This rate must be respected, because an excess of CTAB
would react with SDS and hinder a following SDS-PAGE. (you must know that
CTAB is also used to complex SDS and, by this way to destroy SDS-protein
complexes; so, an extraction of proteins from a SDS solution can be
realized).