Concentrating enzymes

[Frank Fürst]

Phil Harrison wrote:
> 
> I am purifying a fructosyltransferase from plant tissue.  After
> ammonium sulfate fractionation and
> desalting, I have been pooling 4-5 batches and concentrating by
> an Amicon thin channel device.

Why don't you just redisolve or even resuspend the ammonium sulfate
precipitate in some, say
> 
> I am concentrating ca. 200 ml down to ca. 45 ml.  Occasionally I

10 or 20 or, if you like, 45 ml of buffer and dialyse this to desalt
the solution? You'll get nearly no increase in volume. 
We use ammonium sulfate precipitation as a means of concentrating
proteins that don't go well with amicon (aggregation...)! I'm
currently not aware of any protein that would stand ammonium sulfate
fractionation, but not dialysis.

Bye, Frank
-- 
*************************************************************
Frank Fuerst, Institute of Biochemistry of Potsdam University
Im Biotechnologiepark, D-14943 Luckenwalde
Tel.: +49-3371-681334;   Fax.: +49-3371-681339
ffrank at rz.uni-potsdam.de
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