What is the best negative control for an IP? I am using IgG from the same species as the AB of interest. What do you do it it recognizes a band at the same MW as my protein of interest? Is there any better control for an IP of endogneous protein?

In order to answer you in the best way please let me know what are you treing to IP. Do you use a tag to pull down?
I use a non transfected cell line as a negative control. You can also use the same Non spesific IgG type that you are using for the IP.
Write me and I will help you more.
Guy

Its not letting me email so I am posting the reply.
I am IP'ing endogneous nuclear protein our of cell lines and Tissue

Thanks,
So use as a negative control non spesific IgG from the same sp. that your Ab is.
Let know if you had a background
I will ask hear a bit more about nuclear IPs
Guy