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Problems with dialysis

Protein precipitation during dialysis against phosphate or Tris buffers (PBS or TBS) can be often caused by:

  • too low salt concentration (NaCl, KCl)
  • too high protein concentration
  • sudden pH changes
  • pH of dialysis buffer close to PI of a protein
Therefore:
  • use at least 1000 fold excess of dialysis buffer
  • perform procedure at 4c(at least 3 hours, followed by a buffer change)
  • use at least 350 mM salt in the dialysis buffer
  • optional: 50 % glycerol
Precipitated proteins are very difficult to refold. If possible purify your protein again and apply other conditions for dialysis.

Last changed: 2009-04-02 by WebMaster