protein sticking to membranes

Hello,

I am working with a protein that sticks to membranes used in dialysis
and concentrators. I've tried both PES and cellulose membranes. This
makes buffer exchange and concentrating a huge pain. The protein is
well behaved in solution, and the stickiness is not due to
aggregation. I can recover some of my protein by washing the membrane
afterward with buffer, but the yield is not great and inconsistent.
Are there other membranes worth trying? Does anyone else have
experience with sticky proteins?


Thank you,
ho

Dear Ho,

seems you protein likes polar surfaces a lot. Made me instantly think
of non-stick frying pans an thus I would like to recommend teflon
membranes.

Wolfgang

Ho-Leung Ng wrote:

Ho-Leung Ng писал(а):


How do you do your concentration procedure? Do you pre-filter the
concentrator column with a buffer that you use for the protein sample
dilution? Do you have salt in your buffer (some 50-100 mM NaCl).

I personally like Amicon Ultra Centrifugal Filter Units
(http://www.millipore.com/publications.nsf/dda0cb48c91c0fb6852567430063b5d6/614688873e5dcb4185256b3600502444/$FILE/FF1550EN00B.pdf)
that contain the Ultracel - regenerated cellulose, low binding
ultrafiltration membrane. I used these columns for the ultrafiltration
and "dialysis" of more than 10 different proteins, and i almost
exclusively had > 85% recovery.

I mean if you have small amounts of protein - some milligrams, then the
dialysis is quite a dangerous technique to rely on. Gradual sample
dilution combined with ultrafiltration worked always better for me: (1)
i had never problems with protein precipitation; (2) or adsorption.

Best regards,

PH