SDS-PAGE problem!

Andy Hill afh30 at
Fri Jul 21 10:37:52 EST 1995

> I am using BIO-RAD mini-gel electrophoresis system. My target protein is
> about 25-27 KD. I run 12% running gel and 4% stacking gel at 100 V. The
> results I've got were curved and connected bands between lanes. First I
> thought it might cause by high salt concentration in my sample, I diluted
> my sample from 5 ug/ul to 3 ug/ul.The results got better but not good
> enough. I still had curved bands and connections between lanes. It seems
> like both ends of the bands migrate faster than the middle. 
> Could anybody give me some advice? Thanks in advance!
> Cheers!
> Wei


I use the same system and have done for a few years. Here are a few things
you may want to try...

1. Run gels at 200v for 45-50 mins
2. Reduce the amount of detergent (if any) in the sample - this can really
cause problems like those you describe
3. Ensure the gel is really set! 
4. Check the running parameters (ie current, check manual for correct amps
- if they are out then check the composition of your buffer)
5. Try using chilled running buffer - you can usually load the outer lanes
with out them smiling if the buffer is real cold.

hope this helps


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