Dear H.Sin, These references may help you:
Meireles, M., Aimar, P., and Sanchez, V. (2004) Albumin denaturation during ultrafiltration: effects of operating conditions and consequences on membrane fouling, Biotech. Bioeng. 38, 528-534. Schratter, P., (2004) Purification and concentration by ultrafiltration, Meth. Mol.Biol.: Protein Purification Protocols 244, 101-116 Sweryda-Krawiec, B., Devaraj, H., Jacob, G., and Hickman, J. J. (2004) A new interpretation of serum albumin surface passivation, Langmuir 20, 2054-2056. Adding 1% BSA to your buffer and pre-treating the centricon diafiltration membrane does prevent aggregation and improves protein yield by several fold. Additionally, adding 50 mM L-Arginine (pH’ed to buffer) prevented aggregation and produced nice protein crystals. Best wishes, Avinash
