It very much depends on the insert. The protein which you
expressed, generally O.D 0.4-0.6 is applied, and O.D=1.5 also works well
for some induction. The concentration of IPTG is another important factor,
some need higher, some need lower, some even don't need at all(IPTG reduce
the expression), That is why some need a LysS plasmid which carries the
T7lysozme to partially digest T7RNA polymerase. These attribute to the
different protein structres which may be compatible, or may be not in
E.coli. Hope this helps! Cheng
On Tue, 25 Mar 1997, Cheng Luo wrote:
> Path: umdac!umu.se!newsfeed.sunet.se!news01.sunet.se!sunic!02-newsfeed.univie.ac.at!news.ecrc.de!news.cesnet.cz!news.radio.cz!voskovec.radio.cz!newsbastard.radio.cz!news.radio.cz!newsbastard.radio.cz!news.radio.cz!CESspool!btnet-feed2!unlisys!cs.tu-berlin.de!zrz.TU-Berlin.DE!news-ber1.dfn.de!news-ham1.dfn.de!news-han1.dfn.de!news-koe1.dfn.de!main.Germany.EU.net!EU.net!enews.sgi.com!news.corp.sgi.com!news.sgi.com!howland.erols.net!cyclic.gsl.net!news.gsl.net!news-hk.gsl.net!news.gsl.net!newsgate.cuhk.edu.hk!newsfeeder.ust.hk!news.ust.hk!boella
> From: boella at uxmail.ust.hk (Miss ELLA CHAN)
> Newsgroups: bionet.molbio.proteins
> Subject: Q. About Protein Expression !!!
> Date: 11 Mar 1997 16:20:01 GMT
> Organization: Hong Kong University of Science and Technology
> Lines: 16
> Message-ID: <5g40nh$c25 at ustsu10.ust.hk>
> NNTP-Posting-Host: uststf3.ust.hk
> X-Newsreader: TIN [version 1.2 PL2]
> Xref: umdac bionet.molbio.proteins:8837
>>> Hi,
>> Could somebody kindly tell me what is the optimum OD600 for the induction
> of protein expression in bacterial strain using IPTG?
>> I have been heard that we can start the induction with OD600 = 0.6
> ie. the pre-log-phase or OD600 = 1.5 which is at the late log-phase.
> Which condition should be the best ??
>> Thanks for your help !
>> Regards,
> Ella
>>>> --
> $***********************************************************************$
> $Dr. Cheng Luo Tel. 46 90 165474 $
> $Dept. of Plant Physiology Fax 46 90 166676 $
> $University of Ume Email: cheng.luo at plantphys.umu.se $
> $90187 Ume http://www.plantphys.umu.se/~cheng $
> $Sweden $
> $***********************************************************************$
>>>
