Protein A and protein G - (Jul/16/2008 )

I need to purify a Fc-fusion protein from cell supernatant, as the protein should be secreted due to the presence of an IL-2 ss. I am trying to decide between protein A and protein G affinity chromatography for this purpose. What would one recommend?

Thanks.

-suds-

Principally it doesn't matter. However Protein A is more common and "so-to-say" the "gold standard" (especially in scale ups) and usually a little cheaper. So I would go for Protein A, which is available from various suppliers, e.g. Promega , invitrogen, GE healthcare, novus, ...

any other opinions?

QUOTE (suds @ Jul 16 2008, 10:55 AM)

-Senior_Scientist-

prefer protein A

Protein G picks up bovine antibodies from the FBS in the supernatant

-Minnie Mouse-

QUOTE (Minnie Mouse @ Jul 16 2008, 03:42 PM)

prefer protein A

Protein G picks up bovine antibodies from the FBS in the supernatant

Really does it do that? I heard that Serum would compete with the antibody of my interest to bind to Protein G, but didn't know it's that serious. actually I did immunoprecipitation with Protein G and I am getting some bands that are not my antibody on SDS-PAGE. my protein is about 25KDa but I got some bands 70-100 KDa

-Curtis-

I agree with the other answers - I also used protein A.

-vista-