prot A vs G beads --> CO-IP vs NO-IP! - (Dec/04/2006 )

I have a very strange problem:

When I do IP's with prot A beads together with rabbit poly clonal antibodies, it works well.

But when I switch to mouse mono clonal antibodies together with prot G beads, I do not see any IP... (with different AB's, that normally should work in IP). When I run a coomassie gel after the complete procedure, the antibody-bands are visible. So, the AB's are bound...

The beads are stored in a buffer containing 20 % ethanol. Before use I wash the beads 3 times shortly. Isn't this enough? (and can this be the cause?)

Can anybody help me?

The problem is strange, isn't it?