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Protein fractionation using electrostatic interactions in membranel filtration
Author(s) -
van Eijndhoven Raymond H. C. M.,
Saksena Skand,
Zydney Andrew L.
Publication year - 1995
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260480413
Subject(s) - fractionation , filtration (mathematics) , chemistry , chromatography , size exclusion chromatography , biochemistry , mathematics , statistics , enzyme
Abstract One of the critical factors limiting the development of membrane systems for protein fractionation has been the poor selectivity that has generally been obtained with these membrane devices. We have demonstrated that it is possible to dramatically improve the selectivity of available membrane systems by exploiting the different electrostatic interactions between the two proteins and the membrane. The separation factor for the albumin‐hemoglobin system could be increased to more than 70 simply by reducing the salt concentration and adjusting the pH to around 7 (near the isoelectric point of hemoglobin). This very high selectivity was a direct result of the strong electrostatic exclusion of the charged albumin from the membrane pores under these conditions. This high selectivity makes it possible to very effectively separate these albumin‐hemoglobin mixtures using membrane filtration, and this was demonstrated experimentally using both a simple batch filtration process and a continuous diafiltration system. The hemoglobin recovery in the diafiltration experiment was greater than 70% after a 3‐diavolume filtration, with the Hb purification factor being around 100 under these conditions. These results clearly demonstrate the potential of membrane systems for the fractionation of proteins even with very similar molecular weights. © 1995 John Wiley & Sons, Inc.