SDS-PAGE problem

Jayakumar R jakku71 at
Mon Nov 19 18:27:23 EST 2001

   I am having a problem with a traditional large format SDS-PAGE that I
have been doing.  I run a 20X23 cm SDS-PAGE gel (7%) at 36mA constant
current for stacking gel and 50mA for running gel for 6-7 hours.  The bands
appear very diffuse (proteins are BSA in all lanes and a high molecular
weight marker).  The electrophoresis temperature is 10C.  The polymerization
temperature is 23C. The concentration of Bis in the gel is 1.6% (double the
normal of 0.8%). The Bis concentration is high since I need to use the gel
for seperating two proteins which differs by only 1 kDa. So the diffuse
bands is going to cause me a lot of problems when I use it for that purpose
which brings me to the second part of this question.  Which conditions are
the best for separating two proteins which differ by hardly 1 kDa?
    Any tips would be gratefully acknowledged since I am at my wits end with
these two strange problems.  Praying.............
Jayakumar R. nair
Dr. John J. McGuire's lab
Grace Cancer Drug Centre
Roswell Park Cancer Institute
Elm and Carlton St.
Buffalo, NY14263.
Tel: (716)-845-8918 (off)
     (716)-833-0704 (Res)
Email: jakku71 at

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