I purify scFv's all the time using a specific cation-exchange resin
(PolyCAT A) from the Nest group. They sell several sizes of the column,
and it has extremely low back pressure, so I connect it to a Pharmacia
FPLC. This system has the advantage of being very general for scFv's
(thatalmost always have very high pI values). The actual purification
wasworked out several years ago by people at Genex (now a part of
Enzon). Here's a couple of references to get you started:
Whitlow, M.; Filpula, D. Single-Chain Fv Proteins and Their Fusion
Proteins, Methods: A Comp. to Meth. in Enzymol., 1991, 2, 97-105.
Stewart, J.D.; Lee, I.; Posner, B.A.; Benkovic, S.J., The Expression of
Properly-Folded Catalytic Antibodies in Escherichia coli, Meth. in
Enzymol. 1995, 249, 507-519.
Hope that this helps.
Department of Chemistry