A fastidious contaminant

[Giorgio Spagnol]

Dear fellow netters,
When I precipitate a glycoprotein I'm studiyng with a monoclonal Ab 
against the peptidic part, two contaminants of lower molecular weight 
(It actually seems one, when I run nondenaturing gels) always 
co-precipitate. Consider that the protein is precipitated after 
extraction of integral membrane proteins with 1% Triton and eluted from 
the antibody at high PH and exchanging triton with octylglucosyde, 
always at physiologic pH.
If anybody could help me in get rid of this fastidious contaminant, I 
would be very grateful.
Cordially,
Giorgio Spagnol