Slow running SDSPAGE gels answered

[Fergus Doherty]

Many thanks to all those who replied to my question about our problem with
slow running SDS mini-gels.  I think the problem is solved and is
embarassing to explain - but what the heck.

I use the Hoeffer mini-gel system.  The problem occurred mostly when my
technician ran the gels (honestly!), and he made up more electrode buffer
than me and poured any excess after filling the upper chamber into the
lower chamber.  If there is only one gel on the rig then the unused upper
chamber electrode (which actually goes down to the bottom of the core) can
be covered with buffer from the lower compartment!  Running at constant
current this must mean that the current actually passing through the gel is
very small (presumably teh voltage is low, we never check that).  Anyway,
if you just put a glass plate where the second gel should go and hide the
spare electrode then the gels run much quicker. OK, so I haven't
experimented with it yet to check this all out, but so far all the gels
have run in the normal time.  Someone did suggest this - (thanks AG Goetz,
thanks to all).  What a twit I am.  BTW storing home-made gels is
definitely not the problem.  We store them wrapped in cling film in a moist
box in the fridge.

Fergus Doherty,
dept. Biochemistry,
University Medical School,
Queen's Medical Centre,
Nottingham NG7 2UH
Tel: 602 709366  FAX 602 422225 Internet: mbxfd at unicorn.nott.ac.uk