Proteins differing by 1 kDa

R. John Lye rjl6n at virginia.edu
Thu Jan 3 07:20:07 EST 2002


"D.K." wrote:

> alx_bu at yahoo.com wrote:
> >I have serious doubts that you'd be able to see the 1 kDa difference at 65
> >kDa target on the SDS-PAGE (unless you'll make an ultra-extra-big one). I'd
> >say, the only viable alternative is to do MALDI or other mass-spec opn the
> >sample.
>
> I bet it is easy. Just run the gel longer.

Also, try playing around with different batches of SDS. The ultra-pure
stuff, that some people seem to think is necessary, does not necessarily
give the best separation for some proteins.  Back when I was in grad
school, we found that the cheapest Sigma SDS we could find gave us
the best separation between alpha and beta tubulin (which have very
similar molecular weights).  Apparently some of the long chain
contaminants help to increase the separation.

Good luck,
John






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