Rf: PAGE: Run times and voltages

Ian A. York iayork at panix.com
Tue Oct 31 11:50:40 EST 1995

In article <475928$km0 at mserv1.dl.ac.uk>,
LOGAND  <logand at msdos.ensam.inra.fr> wrote:
>Nicholas Moody wrote:
>>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.
>The advantage is that you then have time to do other experiments or prepare 
>your staining solutions. 

I think that's probably the main advantage with most gel rigs, but if 
your apparatus doesn't have some kind of cooling effect, or if it doesn't 
have the plates sitting in buffer to equilibrate, then a slightly slower 
run is likely to give better results.  The fast run generates a fair 
amount of heat, and the heat is not evenly distributed, so you get 
localized hot spots, and the current changes in those regions.  The 
result is uneven running.  

Most if not all of the minigels have some way of looking after this, so 
slowing them down isn't going to gain much.  With the large gels, the 
older ones (that basically just support the top and bottom of the gel 
with buffer pools at top and bottom, with the rest of the gel plates 
bare) work best at a medium votage/current.  Some of the new gel rigs 
(Hoeffer's and some others) have cooling menthods, and my impression is 
that these give nicer gels; but the difference is not huge.

Ian York  (iayork at panix.com)
Dana-Farber Cancer Institute, 44 Binney St., Boston MA 02115
Phone (617)-632-3921     Fax  (617)-632-2627

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