It could be caused by iron contamination in one of your buffers. We used to buy glycerol in a metal canister and metal would leach into the glycerol. Because of this, one protein that I worked with would turn yellow, even at relatively low concentrations. I did not have this issue when using glycerol from plastic or glass containers though.
Matt On Fri, Sep 24, 2010 at 9:03 AM, Van Den Berg, Bert < lambertus.vandenb...@umassmed.edu> wrote: > Maybe you should give us a hint about the identity of your protein (if > you dare....;-)). I’m sure there are folks around who may be able to say > whether or not your protein is supposed to be brown. You can’t expect too > much help if you don’t provide (m)any details. > > Cheers, Bert > > > > On 9/24/10 4:34 AM, "sandeep" <toskgu...@rediffmail.com> wrote: > > Dear all, > > I have purified protein from E.coli. expression system. the protein has > been purified with three independant columns. Now during concentration step > using amicon, the protein shows brown colour. what could be the reason. > > best regards and Thanks, > sandy > < > http://sigads.rediff.com/RealMedia/ads/click_nx.ads/www.rediffmail.com/signatureline....@middle?> > > >
