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Storage of GST proteins in crude lysates - (Jun/05/2006 )

I've been extracting crude lysates from BL21 e.coli cells using osmotic shock and storing the lysates in PBS and .02% sodium azide at 4 degrees. The bands look the the same on SDS-PAGE for several weeks after extraction, but I'm wondering if it may be degraded under these conditions.

How do you guys store crude lysates (GST proteins especially!) ?

-hayrake7-

QUOTE (hayrake7 @ Jun 6 2006, 09:36 AM)
I've been extracting crude lysates from BL21 e.coli cells using osmotic shock and storing the lysates in PBS and .02% sodium azide at 4 degrees. The bands look the the same on SDS-PAGE for several weeks after extraction, but I'm wondering if it may be degraded under these conditions.

How do you guys store crude lysates (GST proteins especially!) ?

I've tried 4C and -80C. Both have worked OK. As long as you have controlled for bacteria (azide is good), and proteases, cold storage should not be a problem. I'd err on the side of very cold (-80), especially as you've already been using low temperature for the lysis stage.

-swanny-