I have got troubles with protein pruification recently. My protein is a little large, 900+aa, and constructed to pGEX-6p-1, expressed in Rosetta(DE3). The fusion protein exists in supernatant after lysising the cells, while exists more in precipitate. I just take the supernatant to subsequent steps. But eluting the protein from the gst column, I found the purity is very low, no matter I cleave the PrePcission on or off the column. I am sure I have wash off the undisired protein with sufficient PBS. My protein contains 16 Cys, is it make the elution low purity?
So, could anyone help me analyse the problem and provide some suggestion about purification of Cys containing protein
Thanks so much!
Edited by chj, 03 May 2010 - 08:30 AM.