protein sticking to membranes

RNA Master Purple.Haze1st at gmail.com
Wed Aug 30 03:37:00 EST 2006


Ho-Leung Ng писал(а):

> 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

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



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