Hi all, I came across a strange problem. When I purify a protein complex, let's say AB, it will precipitate when I add reducing reagent like DTT or TCEP in the gel filtration buffer, or if I don't include any reducing reagent running column, I take the peak fractions and supplemented with DTT or TCEP, it will also precipitate. And the precipitation is irreversible when I change buffer to non-reducing reagent buffer. But when I purify A or B alone, they don't have this problem. Anyone have some clues for this observation? Thanks a lot.
zhuqing
