Concentrating enzymes

Frank Fürst ffrank at
Wed May 26 13:00:50 EST 1999

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
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