How can I achieve a clear supernatant, after I lyse the cells by freeze-thaw technique? After centrifugation, the supernatant feels very viscous.

I'm trying to express a His-tagged protein in BL21 (E.coli) cells. Until recently, in order to lyse the cells, I would always use sonication. I switched to freeze-thaw, as efficiency was better...

13 July 2014 853 6 View