11 November 2019 5 3K Report

Hy everyone,

I'm facing some troubles when changing the buffer of my protein solution. I'm doing a 2-step purification of my protein, first on a nickel-column and second on a heparin column. Between the two steps I add glycerol to the protein solution in order to freeze it until further use. I need to remove the glycerol and the salt from the former buffer before adding the protein to the heparin column and to achieve this I'm using the Amicon® Ultra-15 Centrifugal Filter Units. However, it looks like this is not the best way to do it, since this process always takes ages and my protein starts to aggregate at the membrane resulting in little flakes in the solution. I guess the aggregation makes it even harder to perform the filtration since the aggregates block the pores of the membrane.

I was thinking about using those Amicon® Stirred Cell models, but I have no experience with them and they are pretty pricy. Can some of you share your experience about the stirred cells with me?

I would be also very happy to hear about other alternatives for buffer exchange that work great!

Thank you very much in advance.

All the best,

Pascal

PS: In case you need to know the compostion of the buffer:

- 50 mM Na-PO4

- 0,5 M NaCl

- 84,6 - 400 mM Imidazol

- 10% Glycerol

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