SDS-PAGE for purity

S.Ballal ballal_sv at
Wed Jul 17 21:06:16 EST 2002

Systematic errors would mean I guess, most importantly, choice of
staining method and setting up the limit when to stop staining ( in
case of silver) or when to stop destaining (Commassie).

You will need a scanner/ densitometer for "percent area
determination:. This is something which should not be done with

In case you know the minimum quantity of contaminant you want to
detect( say 0.1%), then you can load the same amount of the same
protein in another lane (say 0.1% of the loaded protein) and ensure
that same is visible during staining and destaining. This you you can
always prove that you have not understained your silver and
overdestained your CBB stains.

Best of Luck

Indus Biotherapeutics Ltd., Ahmedabad, India

"Artem Evdokimov" <AEVDOKIMOZ at> wrote in message news:<2x2Z8.107752$CJ2.12370968 at>...
> Very cautiously.
> Seriously, though, it's a method that's begging for systematic errors...
> A.G.E.
> <drabena at> wrote in message
> news:20020716143214.1577.qmail at
> > I am currently running SDS-PAGE's to calculate the "percent area" of a
> single protein.  Can anyone tell me how to run this assay to determine the
> percent purity?
> >
> >

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