[Protein-analysis] Re: proteins in urea-SDS

[kaj.stenberg from helsinki.fi.invalid]

Florencia Campetella <fcampetella from gmail.com> wrote:
> Hi, I solubilized a pellet with a buffer containing 70 mM Tris-NaOH [pH 6.8],
> 8 M urea, 2.5% SDS, 0.1 M DTT, 10% glycerol, bromophenol blue, and kept the
> samples on ice. When going to load the gel I noticed some aggregates I
> couldn't get rid off, gelatin-like. It's the first time I'm using this
> buffer so I don't know what could be happening...
> I was told urea is not stable and over time it ionizes and really affects
> your protein sample, can anyone tried to freeze their samples with this kind
> of buffer?

8M urea???
What is the rationale for that? 

-- 
Kaj