Separation of two 55 kD proteins

[Christopher B. Yohn]

I am working on characterizing a set of purified proteins.  There are two
55 kD proteins within the set of proteins.  On a 1D Laemmli SDS-PAGE, you
can just make out a doublet at 55 kD.  I need to further prove that there
are in fact two proteins.  I tried 2D IEF with the highest range
ampholines I could find, and one of the proteins is still too basic to
enter the gel - sometimes I can just see it at the basic end.  I tried
NEPHGE, but the proteins would not resolve well under non-equilibrium
conditions.  I've also tried different percentage (and gradient) 1D gels
(all Laemmli or Chua).  I cannot reproducibly resolve these two 55 kD
proteins because of the basic nature of one of them.  Does anyone have a
suggestion for resolution?  Any and all comments appreciated. TIA.
                                    -chris

-- 
Christopher B. Yohn  [cyohn at scripps.edu]
The Scripps Research Institute
Dept. of Cell Biology - MB8
La Jolla, CA  92037
Ph: (619) 554-4335
Fax: (619) 554-6188