Abstract—Equilibrium and kinetic experiments have been
carried out in order to study the effect of protein size in the
purification of high molecular weight (HMW) proteins by IEC.
The current work focused on two proteins uptake by Q HyperZ
chromatographic media. Bovine Serum Albumin (BSA) and
ferritin have been selected due to their close isoelectric point
(4.9 and 4.4 respectively) and their different molecular weight
(66.5 and 450 kDa respectively). As usually reported in the
literature, equilibrium uptake for BSA has been higher than for
ferritin at the same buffer conditions (pH, ionic strength),
suggesting complex phenomena for ferritin uptake. Moreover,
contrary to the general rule in ion-exchange processes, ferritin
uptake has not been really affected by the increase of NaCl
concentration. In fact, no significant change in the ferritin
uptake has been quantified with the increasing of salt
concentration from 0 to 100 mM. However, the kinetics of
ferritin ion exchange has showed a classical behaviour,
according to the homogenous diffusion model. The
determination of the effective diffusion coefficient for ferritin
has been possible from transient uptake at different protein
initial concentrations. Thus, in spite of its large size, ferritin
seems to diffuse inside the macro-porous anion-exchange
particles.
Index Terms—Ion-exchange chromatography, isotherm,
kinetic, protein purification, Q HyperZ.
The authors are with the Institut National des Sciences Appliquées,
Toulouse, France (e-mail: wakkel@insa-toulouse.fr, alfenore@insatoulouse.
fr, mathes@insa-toulouse.fr, mafernan@insa-toulouse.fr).
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Cite: M. Wakkel, S. Alfenore, S. Mathé, and A. Fernández, "Equilibrium and Kinetics of High Molecular Weight Protein Uptake in Ion Exchange Chromatography," International Journal of Chemical Engineering and Applications vol. 6, no. 5, pp. 306-313, 2015.
