Mapping the chromatographic behavior of a cell proteome utilizing orthogonal routines: the influence of feedstock pH

Surface charge, molecular weight, and folding state are known to influence protein chromatographic behavior onto ion-exchangers. Experimentally, information related to such factors can be gathered via two-dimensional electrophoretic (2-DE) methods. The separation behavior depicted by the insect cultured-cells proteome, which is an important host for recombinant protein production, was explored in this study. Experimental evidence showed a correlation between apparent isoelectric point distributions and the mobile phase conductivity. It was observed that the information contained in the isoelectric point (pI) value(s) obtained with a 2-DE routine showed a good correlation with the IEX chromatographic behavior, for a number of commercial adsorbents. This correlation was observed irrespective of the pH of the feedstock within the range 6 to 8. An initial prediction of protein ion-exchange chromatographic behavior could be possible utilizing an experimental approach based on the mentioned orthogonal methods. This technique is providing information that more closely resembles the separation behaviour observed with a complex biotechnological feedstock.Keywords: Insect cells, proteome, chromatography, ion-exchange, bioprocessingReceived: 3 August 2008 / Received in revised form: 15 August 2008, Accepted: 19 August 2008, Published online: 20 August 2008