[Protein-analysis] Re: higher bands than expected

Duncan Clark blackhole at abuse.plus.com
Fri May 12 05:37:19 EST 2006

Historians believe that in newspost 
<mailman.884.1147183498.16885.proteins at net.bio.net> on Tue, 9 May 2006, 
FAROOQ SABAR <farooqsabar at yahoo.com> penned the following literary 
>I purified my protein and analyzed on SDS-PAGE. There
>was only a single band of required size which is about


>I stored the protein solution at 4degrees C and
>now after three months when I run the protein on 8%
>SDS-PAGE there are multiple bands. All bands are above
>the required size except a line like band at the dye
>front. Note that I am using three months old stock of
>gel running buffer and SDS solution. Is there some
>thing wrong with the protein or gel or loading buffer?
>Can some one guide me? Thank you.
>Muhammad Farooq Sabar

It sounds like the band at 19Kda ran as fully denatured protein subunit 
i.e. monomer and the later gel is running as not fully denatured protein 
so you see dimer, trimer etc.

It could be the gel, running buffer or more likely the loading buffer 
has gone off. That is assuming that you did put it in loading buffer for 
a couple of mins in boiling water to denature the protein before loading 
the gel?

I love deadlines. I especially like the whooshing noise they make as
they go flying by.

Duncan Clark
GeneSys Ltd.

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