Extracting enzymes from E. coli

Cornelius Krasel krasel at wpxx02.toxi.uni-wuerzburg.de
Tue Dec 5 05:01:44 EST 2000

Dima Klenchin <klenchin at facstaff.remove_to_reply.wisc.edu> wrote:
> arsphys at cc.usu.edu (Phil Harrison) wrote:


> :2.  Would freeze-thaw cycles in liquid nitrogen disrupt the cells?
> If only one cycle then only a bit. Three cycles will but that's not
> really mild condition. If you pretreat bugs with lysosyme, then
> one cycle will do. 

It also depends on the bacteria. BL21(DE3)pLysS which coexpress lysozyme are
quite sensitive to freeze-thawing, because the freeze-thaw cycles release
the cytosolic lysozyme which then attacks the outer membrane of the
bacteria. Most other strains are less affected.


/* Cornelius Krasel, U Wuerzburg, Dept. of Pharmacology, Versbacher Str. 9 */
/* D-97078 Wuerzburg, Germany   email: krasel at wpxx02.toxi.uni-wuerzburg.de */
/* "Science is the game we play with God to find out what His rules are."  */

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