Bernard Murray, PhD spam at
Mon Jan 31 15:17:04 EST 2000

In article
<Pine.A41.4.10.10001291404020.113936-100000 at homer30.u.washington.edu>,
moser at u.washington.edu ("'Mike' Michael J. Moser") wrote:
> I use Protease inhibitor cocktail tablets from Roche.  They seem to work
> well.  Unfortunately they are very expensive.  They inhibit a wider
> spectrum of proteases than PMSF though.  There are also more stable
> analogs of PMSF available.  Again they cost more than PMSF does.

AEBSF (or PefaBloc) is equivalent to PMSF but is stable in aqueous
solutions.  I think Roche has this and a variety of others in its
(unnecessarily expensive) cocktail.

> On Fri, 28 Jan 2000, simm wrote:
> > I am currently running experiments requiring the use of PMSF. I have to
> > prepare fresh solutions each time which as you may know takes
> > up time and wastes a lot of the reagent.
> > I am specifically interested in stability of PMSF in methanol,
> > acetone and isopropanol over time. I have heard some colleagues
> > store such solutions for up to a month, but I need
> > confirmation from the scientific body.

PMSF is fine in 2-propanol as long as it remains dry.
I have used such solutions for months without problems
(but have not formally tested the protease inhibition
activity).  I keep the stock solution in an tightly capped
container and limit the amount of time I leave it with
the lid off.

Bottom line:
   Use fresh PMSF for large volumes and AEBSF for small.


Bernard P. Murray, PhD
bpmurray at cgl . ucsf . edu
Department of Cellular & Molecular Pharmacology, UCSF

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