Form of Betaine

Fri Feb 5 21:35:00 EST 1993

-----------Lenny writes -----------------------------
Hi Netters

        A short while ago there was a discussion about expressing fussion
proteins in E. coli in which several people recomended using 25 dC growth 
temp and Sorbitol and Glycyl Betaine in the medium as described in the 
Blackwell and Horgan paper (FEBS, 1991, 245(1,2,3)10-12).  I want to try 
it, but there are several forms of Glycyl Betaine listed in Sigma (the 
source cited in the paper).  In the Sigma catalog, page 159, should I use
#B-2629 (free base, anhydrous), #B-2754 (free base, monohydrate), or #B-3501
HI Lenny!
    We have tried both the monohydrate and the hydrochloride 
and both have the same effect (good amounts of protein produced).
 My student likes the monohydrate as there are less warnings 
on the bottle. 
    A few hints about this protocol:
    The doubling time in this media is dramatically
    increased!!!! We do a 1/100 diln of our overnight    
    and it takes 18 hrs to go to the appropriate density (0.5-1.0).
    Induction for 2 hrs is still the best for us with pGEX.
    (No benefit to inducing longer ; 4 or 6 hrs)
Good Luck!
Dan Gietz
Department of Human Genetics
University of Manitoba
770 Bannatyne Ave, Rm 250
Winnipeg, Man, Canada
R3E 0W3

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