PAGE: Run times and voltages

Giovanni Maga maga at
Tue Nov 7 06:11:58 EST 1995

In article <1995Oct31.025700.29994 at>, Nick Moody
<nicholas.moody at> wrote:

> It is standard practise in our Department to run SDS-PAGE gels at 200V 
> until the dye front reaches the end of the gel (usually 45 miuntes). In 
> other papers I have read they use lower voltages for longer times (eg 40V 
> for 3 to 4 hours). Can anyone tell me if there are any advantages in 
> using lower voltages and longer times. I use 10% discontinuous SDS=PAGE 
> gels and need to silver stain them.

Sometimes, high voltage can give troubles in the resolution of bands
(smiling effects, smears), but the limit depends on the buffer system you
are using, the AA/bisAA ratio, the gel% and also on the amount of proteins
you add. I am not aware of any general rule, but the empirical one (try
and see). In my case, I usually run SDS-PAGEs of 6, 7.5, 10 or 12% either
for blotting or for staining (silver, comassie) at 80-90 V until the
proteins enter completely the lower gel, then I shift up to 130-140 V
until the dye reaches the bottom. It takes about 1 h with a small gel
apparatus (given that the upper gel is about 0.5 cm high).

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