Re: [ccp4bb] Vivaspin vs Amicon Ultra

[Roger Rowlett]

The vivaspins are the best thing in ultrafiltration since sliced bread. I learned about them while I was at the NIH several years ago and haven't looked back. Fast and low-binding. PES membranes are superior for minimizing protein binding, and are also less subject to pore shrinkage in high salt solutions, unlike cellulose or nylon membranes. I will hardly use anything else for protein concentration. Cheers, _______________________________________ Roger S. Rowlett Gordon & Dorothy Kline Professor Department of Chemistry Colgate University 13 Oak Drive Hamilton, NY 13346 tel: (315)-228-7245 ofc: (315)-228-7395 fax: (315)-228-7935 email: rrowl...@colgate.edu On 10/5/2011 8:59 AM, Peter Gutte wrote: Hi Jan, In our lab we use both the Amicon Ultras and the Vivaspins  (soluble and membrane proteins). What I can tell you is that me and a few other colleagues had the experience (and still do) of specific soluble proteins precipitating on the Cellulose membrane of the Amicon. By  switching to the Vivaspins, which have a polyethersulfone  membrane, the precipitation completely vanished. This  seems to be very protein dependend as many seem to be able to use both systems with no or little problems. I don't know if the type of membrane really makes the difference but it could be a possible explanation. I unfortunately have less expierence with these systems on membrane proteins and I only know that both systems seem to work fine for colleagues who work on membrane proteins. Best Regards, Peter