Protein complex stability in SDS laemli buffer

Phillip Robinson mdpjr at
Wed Sep 18 01:04:09 EST 1996

This topic has risen its head several times before.  My experience is
that some proteins retain their associations in the presence of SDS.  It
isn't necessarily covalent association.  Two egs are phospholamban
pentamer (Sarcevic, B., et al (1989) J. Biol. Chem. 264, 20648-20654)
and dynamin tetramer (Liu, J.-P. et al (1996) J. Neurochem. 66,
2074-2081).  Of these types of protein, most (all?) dissociate upon
boiling.  In some other cases it simply relates to the presence or
absence of a reducing agent.  This is not the case for many proteins, at
least like the phospholamban above.  Therefore some protein-protein
interactions are SDS-resistant.  I believe some labs refer to this
phenomenon as "SDS-resistant complexes".

I don't know how you could prove this in your case, due to your
aggregation problem.  Perhaps urea?


Inger Natvig wrote:
> We are currently working to characterize a receptor-ligand complex
> belived to be non covalently associated.However,when run on SDS-PAGE
> according to Laemlis procedure this complex seems to be covalently
> associated .Which involves incubation in 2% SDS sample buffer at 37¤C
> for 1 hour, before loading on 1% SDS-PAGE.Does anyone has comments to
> protein complex stability under. I should also mention that boiling in
> SDS buffer result in protein aggregation.

Phillip J Robinson                           ,    
Newcastle, NSW AUSTRALIA                 ;--_|\   
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Email: mdpjr at        \_;--._/  

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