This pH is generally incompatible with Ni IMAC, sorry :) If you have a high pI your best bet is to employ ion exchange as primary capture, specifically SP resin or if you're really lucky - CM resin. There are only relatively few proteins in E. coli that bind to CM resin at pH 5 and virtually none (one-three) that will bind at pH 8. If your protein still binds, then you're good to go.
Artem On Thu, Mar 1, 2012 at 10:49 PM, anita p <crystals...@gmail.com> wrote: > Hi all, > Has anyone used sodium acetate buffer pH (4-5) for purifying histag protein > on Histrap column (AKTA) followed by SEC? > My protein has a pI of 9. I tried pH7.4 but it has precipitation problems. > While doing buffer screening using 24 well hanging drop I found that lower > pI onces are clear, so just thinking can I use Na acetate at pH 5 for whole > purification??? > > > Thanks in advance > Anita
