Protein SDS-PAGE

Hiranya S. Roychowdhury hroychow at NMSU.EDU
Wed Nov 25 11:37:44 EST 1998

At 04:32 PM 11/22/98 -0500, Qiang Zhang wrote:
>hi, everyone, i have a question about Protein SDS-PAGE. i run the gel which
>is 0.75mm thickness, 2cm height of stacking get plus 12cm height of
>separating gel under constant current of 30mA for two gels(15mA for each).
>it runs so slowly that takes about more than 10 hours to run to the bottom.
>the time is much longer than that in my lab's protocol. the concentration of
>the stacking gel and separating gel are 3% and 10% respectively. i am sure
>that there is no error in my all buffer. is there anyone who has experience
>in it can give me some advice about why it is so slow and what i should
>check about it. how long do you spend to run the gel like this? thank you
>for your help and advice.

Usually, such a gel (assuming a width of ~20cm) would be run at 25-30 mA per
gel. Try that. Alternatively, run it at a constant volatge of 150V. It
should take about 3h(+/-1h) to run.
Now, the conditions above are given assuming that your buffers are in the
right concentrations.

Dr. Hiranya Sankar Roychowdhury
Plant Genetic Engineering Lab.
New Mexico State University
Las Cruces, NM 88003
Ph. (505) 646-5785
hroychow at

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