proteins in urea-SDS

[Pow Joshi]

On 3/9/07, 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?
> Thanks!!

ah! it is'nt a good idea to keep samples with SDS on ice .... SDS
precipitates, forms crystals.... and I suppose the urea, at that
concentration would do the same as well.....also, I was wondering what
you mean by tris-NaOH at pH 6.8 ...I suppose you are'nt using tris
base?

pow
>
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> Florencia.
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