Michael L. Sullivan mlsulliv at
Tue Apr 9 10:07:34 EST 2002

Are you running molecular weight markers on your gel?  How do they
look?  That should tell you if your gel is OK.

I think probably your lanes are overloaded with sample.  I think it's
very hard to get good resolution with so much protein being loaded.
I think maybe you should be loading about 1/10 as much protein.
Also, in my experience, sometimes low molecular weight proteins run
better on SDS PAGE if the sample volume is kept small-- on the order
of less than 5 ul per lane.  Hope these suggestions help.


>We have troubles with the detection of proteins of 12 - 25 kDa in 15%
>SDS-PAGE and Western blots. The proteins comes from tissue extracts (aortas)
>and we are using 100 - 200 µg of total protein per lane. The proteins of low
>molecular weight appears as a smear and is impossible to differentiate any
>band. In some cases this proteins appears as M shaped bands. Do you think
>that the problem is the acrylamide or there is any other problem in the gel
>or in the sample.


Michael L. Sullivan, Ph.D
U.S. Dairy Forage Research Center
1925 Linden Drive West
Madison WI, 53706

(608) 264-5144 Phone
(608) 264-5147 Fax


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