sorbitol/betaine system revisited

Chunguang Wang wang at
Thu Aug 12 09:18:04 EST 2004

Hello, everyone: 

In fact I have learned something from this net to solve several
problems in my work before I really post soththing here now for the
first time.

I am planning to try the expression with LB/sorbitol/betaine, which I
also learned from this net. But still sth unclear:

The first trial today showed that the growth in this medium is really
slower than in normal LB (E. coli strain BL21(DE3)pLysS with pET
plasmid). Why? and more importantly, how to do with it? I looked
through some papers saying that sorbitol/betained is supplemented just
before induction. But that also means that the LB, or whatever medium,
will be diluted by sorbitol at least, since the concentration of
sorbitol is not so low. Is that OK for the E. coli?

The main idea of this protocol is that betaine will be recruited into
the cell and will help the protein to be soluble. Then what we should
take care during cell lysis? Some betaine should be added in the lysis
buffer to maintain the enviroment for the protein? and how much if

Several people have said that this system works ok for your protein.
How did you deal with these problems?

Thank you very much in advance for any reply or suggestion!


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