desalting/concentrating low MW proteins

Sebastian Bunka Sebastian.Bunka at
Thu Feb 4 07:00:31 EST 1999

Eugene Hone <eugeneh at> wrote:
> Hi,

> Does anyone know of/have a method for concentrating and desalting a solution
> containing a 4kDa protein?

> Cheers
  Have  a look in the sigma catalog - techware. They have
  a product called Biodialyser using ultrafiltration mem-
  branes. They offer membranes with 500 and 1000 Da nomi-
  nal MW linit. Might work - never tried.
  Just dialyse against ammonium acetate buffer, and  then
  lyophilize   your   protein  solution.  The  NH4OAc  is
  volatile and can be mostly  removed  by  lyophilization
  (depending on the amino acid composition !! up to 99 or
  more percent can be removed - ref. Handbook of HPLC for
  the separation of AA, peptides and proteins, Vol II ed.
  Hancock, CRC Press 1984). So you only  concentrate  the
  protein  but not the salt. Just dissolve in appropriate
  amount of desired buffer.


Sebastian Bunka, Dr. med. vet
Inst. Med. Chemistry, Vet. University Vienna
Ph. +43-1-250 77 ext. 4208, Fax: ext. 4290
e-mail: Sebastian.Bunka at

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