Frozen competent YRG-2 cells made by Stratagene

Rich Buckholz RGB12955 at
Fri Feb 16 10:00:22 EST 1996

I don't know the protocol Stratagene is using, but there is a commercial
kit for making frozen competent cells, sold by Zymo Research in CA.  I
don't work for them or have anything to do with the company, but have used
the kit and find it works pretty well and is not too expensive (I figured
it out one day and I think one $60 kit is enough to do about 600
transformations, theoretically).  I don't believe the efficiency is quite
as high as for LiAc, but it doesn't require any carrier DNA or heat shock
steps.  Their phone is 714-288-9682 and email is zymo at


In article <1996Feb14.203056.74967 at>, C Monfries
<cmonfrie at> wrote:

> Is there anyone out there who knows what method Stratagene are using to 
> make their YRG-2 frozen competent cells? I am using these cells at the 
> moment in the two-hybrid system but would like to be able to transfect my 
> own clones with the cDNA library - i.e., screen sequentially.
> It seems likely that the method uses 2-mercaptoetanol or DTT with 
> Sorbitol added to the media and plates to increase cell viability. The 
> only method I have found so far is that of Brzobohaty & Kovac (1986). 
> Have there been any modifications or improvements since then?
> Thanks in advance,
> Clinton.

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