PAGE: Run times and voltages

Giovanni Maga maga at vetbio.unizh.ch
Tue Nov 7 06:11:58 EST 1995


In article <1995Oct31.025700.29994 at marlin.jcu.edu.au>, Nick Moody
<nicholas.moody at jcu.edu.au> 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).
Giovanni.



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