Dialysis of Small Proteins and Peptides

[Denise]

I have a problem, I have peptides and proteins smaller than the dialysis cut off of 3500 MW.

How can I dialyze these when they are so small and will go through the pores???

thanks a lot guys,
Denise

[kmunson779]

You could buy a smaller cut-off tubing. I know there are brands that go down to 1 kD cutoff.

What are you trying to do with your dialysis? Concentrate? Desalt? Depending on the application there might be an alternative technology.

[proteaAmanda]

Hi Denise,

As kmunson has asked, what are you trying to do with the dialysis? If you are trying to desalt and concentrate your sample as they have suggested, an alternative technology to dialysis is the use of products designed for reversed-phase solid phase extraction of peptides and small proteins. An example is Protea Biosciences' LithTips. These are functionalized pipette tips that are effective for desalting and concentrating peptides and small proteins, depending on the chemistry. They offer C18 LithTips which are effective in desalting and concentrating peptide and small-sized protein samples. I hope this is helpful .