Dear Reza, It sounds to me like an aeration issue. I don't of course know how the 3 ml culture is grown, but if say the small culture is less perfectly aerated and slightly anaerobic, slower growth would mean slower metabolism and slower protein production as well so things do not build up so easily in inclusion bodies. I've had something like this happen in the past. The case I'm talking about was that the protein did not express in aerobic conditions (4 L flask, 500 mL of culture), when I increased the liquid volume to 2-3L in the flask, the culture became slightly anaerobic and protein production turned on. Perhaps this is your case as well. Might be worth a shot!
Cheers, -Tiit ------------------------------------------------------------------------------ Tiit Lukk Staff Scientist CHESS 200L Wilson Lab Ithaca, NY 14853 phone: 607-255-5717 e-mail: [email protected] url: http://www.chess.cornell.edu On Thu, Mar 19, 2015 at 3:33 PM, Reza Khayat <[email protected]> wrote: > Hi, > > > > We can express quite a bit of soluble protein when growing 3ml cultures. > However, the protein becomes insoluble (inclusion bodies) when we scale up > to 500ml cultures. Has anyone experienced such a problem, and found a > solution to it? Thanks. > > > > Best wishes, > > Reza > > > > Reza Khayat, PhD > > Assistant Professor > > Department of Chemistry > > City College of New York > > New York, NY 10031 > > http://www.khayatlab.org/ > > 212-650-6070 > > >
