SDS-PAGE - Dimer formation after boiling?

[Bean Long]

DK wrote:
> In article <452334c6$1 at clarion.carno.net.au>, ben.long at yourfinger.anu.edu.au wrote:
>> I've also just heard from a 
>> colleague that using a reducing agent during protein extraction goes a 
>> long way to minimising polymerisation of proteins on subsequent reducing 
>> gels.  I would have thought that it doesn't matter until you run the 
>> gel.  Any thoughts on this?
> 
> I don't believe it. Reduction is either ~ complete or not in gel sample. 
> Heat-dependent/SDS-resistant polymerization in question has nothing 
> to do with reduction, it's just a property of some proteins to form 
> SDS-resitant oligomers when native structures are unfolded by 
> SDS/heat.
> 
> DK

Agreed, thanks DK.  I came across a comment on an old discussion group 
that dimers, trimers etc. of relatively hydrophobic proteins can form in 
gels after heating.  Presumably they have very hydrophobic cores which 
interact upon unfolding.  This could be an explanation.  I'll try the 
low temp approach.

BTW, what's your reason for using sucrose instead of glycerol?  Does 
glycerol interact too closely?

Cheers and thanks once again,

-- 
Bean

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