Hi, I am working with a serine protease. As the protein is not soluble I am purifying it from the inclusion bodies followed by refolding. The protein shows good activity after refolding but the major concern is the 'precipitation'. Though the protein express quite well, but I loose almost 50-60% protein during refolding (Buffer: 100 mM Tris pH 8.0, 125 mM MgCl2, 100 mM KCL, 5% Glycerol, 2 mM GSH, 1 mM GSSG and 1 M NDSB) as it precipitates. Refolding is done in room temperature. I tried refolding at 4 degree, but it even end up with more precipitant. It also precipitates during concentrating, so in general I almost loose most of the protein during this refolding and concentration steps. I start with 6 lit culture that give around 1-2 mg protein in the final step, which I am not happy with. ​ Any suggestion to deal this issue would be highly appreciated.
Thank you in advance. Best, Dipankar​ -- *Dipankar Manna, Ph.D* Postdoctoral Researcher Department of Molecular Medicine Institute of Basic Medical Sciences University of Oslo, Domus Medica Oslo, Norway Mob : +47 451 66 517 <451%2066%20517> E-mail: dipankar.ma...@medisin.uio.no <dipankar.ma...@kjemi.uio.no> dipankar.biot...@gmail.com http://www.med.uio.no/imb/english/people/aca/dipankam/