Polyacrylamide Gel Shrinkage

hardies at thorin.uthscsa.edu hardies at thorin.uthscsa.edu
Sat May 6 12:16:19 EST 1995


In article <70784.reese at msscc.med.utah.edu>,
 "reese at msscc.med.utah.edu" <reese at msscc.med.utah.edu> writes:
> On 6 Apr 1995 09:26:46 -0700, 
> "Victor DeFilippis"  <vicdef at BIOLOGY.BIOSCI.WAYNE.EDU> wrote:
> 
>>I'm having trouble with 80 cm 6% polyacrylamide gels.  They pour
>>fine and then sit overnight to be run in the morning.  ...
>>... the gel has actually 
>>polymerized so that it's come away from the spacers about a 
>>millimeter or so (shrunk)....  It is necessary to pour these
>>gels the night before as they take a long time to polymerize and a 
>>very long time to run....
>>
>>vicdef at biology.biosci.wayne.edu
>>
> Victor, 
> I don't understand why it takes so long for your gel to polymerize. I don't 
> claim to be an expert, but I have run many PAGE gels. Are your reagents 
> fresh? Stock Acrylamide/ Bis solutions should not be more than about a 
> month old. Perhaps you aren't using enough polymerizing agent. These are a 
> few of the areas I can think of to look. If you can get your gels 
> polymerized in a shorter time (I allow 1 hour for mine) it will eliminate 
> the need to go overnight. Good luck.
> 
> Van Reese

Van Reese is right; there's something wrong with your gel soln's or your
APS or TEMED.  Slow polymerization routinely causes the channeling problem
you describe.  Note that APS goes off in solution within a day.  Also
the TEMED stock goes off if it's not tightly sealed.
The additional point I would add is that if your gel
polymerizes rapidly as it should, then keeping it overnight (or for
that matter several days) prior to running your experiment won't hurt it,
as long as it doesn't dry out.

Steve Hardies, Assoc. Prof. Biochem., Univ. of Texas HSC at San Antonio
Hardies at uthscsa.edu

Steve Hardies, Assoc. Prof. Biochem., Univ. of Texas HSC at San Antonio
Hardies at uthscsa.edu



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