SDS-PAGE - Dimer formation after boiling?

[Bean Long]

Hi all,

I seem to have a protein forming a dimer on SDS-PAGE after boiling.  I 
usually pre-treat my samples to 70 °C for a few minutes prior to loading 
and seem to end up with both monomers and dimers, but on boiling I seem 
to get dimer formation only.  Is this common?  Any suggestions on what's 
going on and how I can get monomers only??  I use DTT to reduce but have 
seen the same results with mercapto.  Haven't tried omitting a reducing 
agent though.

Any comments welcome.

Cheers,

-- 
Bean

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