Remove SDS from protein preparation

Keith Leppard Keith.Leppard at warwick.ac.uk
Fri Aug 30 06:48:32 EST 1996


Chao-Liang Wu <wumolbio at mail.ncku.edu.tw> wrote:
>
> Dear Netter,
> 
> I would grateful if anyone out-there could give any trick to remove SDS
> from protein preparation.  SDS interfer our protein assay by Bio-Rad
> reagent for Braford methods which is the only choice for my protein due
> to lack of those amino acids contributes to the absorption of Lowry
> methods.  Unfortunately, SDS is involved in the preparation of our
> nuclear binding protein.  I have used ultrafiltration to remove SDS, it
> did not work.  Thanks for your help in advance.
> 
> Yours Faithfully,
> 
> Chao-Liang Wu

I have the following method on file, but used it so long ago I cannot
say how well it worked: Analytical Biochem93, 153, 1979 (Henderson 
et al). Start with dialysed lyophilised protein/SDS. Dissolve in either
acetone/triethylamine/acetic acid/H20 85:5:5:5, or heptane/tributyl
amine/acetic acid/2-butanol 70:10:10:10. Protein ppts after about 1hr
on ice. Wash 2x in solvent and 2x in acetone or heptane respectively.
Salts tend to ppt too, hence start with dialysed protein. Water not 
needed in first mix if acetone not anhydrous. Sometimes need 10-20ul
H2O to get protein to dissolve in second mix. Too much H2O gives two
layers: add more butanol to correct. Keep SDS input below 10mg/ml of
solvent.
Good luck
Keith Leppard



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