APS & TEMED in acid gels
erogers at umbc.edu
Thu Jan 23 09:14:26 EST 1997
On 22 Jan 1997, Bernard Murray wrote:
> In article <1997Jan22.123448.9875 at news.iup.edu>, jford at grove.iup.edu says...
> >If you can the amounts of APS and TEMED, you will change the kinetics of
> >gelation (great, that's what you want).
> Agreed. You can also control kinetics by changing the temperature.
> > You will also change the porosity of
> >the gel - the relative amount of cross-linking.
> Is this really true? I was under the impression that the porosity
> was governed by the % acrylamide and by the ratio of acrylamide/bis
> (or other cross-linker). The concentration of TEMED and/or persulphate
> shouldn't have any effect unless they become limiting - so that the
> gel fails to polymerise completely no matter how long it is left.
> Since they only catalyse the polymerisation of the acrylamide monomer
> they play no real role in the eventual structure of the gel.
> Can someone correct or confirm my assumption?
> Bernard Murray, Ph.D.
> bernard at elsie.nci.nih.gov (National Cancer Institute, NIH, Bethesda MD, USA)
>Yes, the amt of initiators DOES affect the gel. Increasing the amt of
TEMED and APS shortens the polymer chain length. In extreme cases excess
initiator can produce a gel solution which does not appear to polymerize
at all. This from Bio-Rad bulletin 1156. On the other hand, I routinely
add extra TEMED to speed up my sequencing gel polymerization without any
apparent effects. Depends on how analytical your gel has to be I guess.
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