Sonication with PMSF/EGTA produces a precipitate.....why?

Eric Roush edroush at acpub.duke.edu
Tue Nov 4 18:35:31 EST 1997


In article <01bce8a7$e01cfd70$373412ac at dough>, "Doug Hubatsch"
<Doug.Hubatsch at arcm.ca.astra.com> wrote:

> Anybody else come across this?  When I sonicate bacteria in .1 mM PMSF/10
> mM EDTA, add 1% SDS and incubate for 30 min. at RT I get a DNA-like
> precipitate.  I don't think its because of the SDS, boiling the mixture
> doesn't put the precipitate back into solution.  The concentrations for
> PMSF and EDTA are well below other reported concentrations so I don't
> really have any idea what could be causing it.
> 
> Any ideas?

Is there any reason to think that this precipitate is something
other than DNA?  It's been a while since I lysed bacteria, but
I remember the early steps of the process being quite gelatinous
in consistancy, not clearing up until after DNase treatment.

-- 
Eric Roush               When an eel
edroush at acpub.duke.edu   bites your heel,
also coache at aol.com      makes you squeal,
                         pain you feel,
                         that's a moray.



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