Protein ion-exchange adsorption kinetics

Authors

  • J. A. Wesselingh,

    1. Chemical Engineering Dept., University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
    Search for more papers by this author
  • J. C. Bosma

    Corresponding author
    1. Dept. of Industrial Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands
    • Dept. of Industrial Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands
    Search for more papers by this author

Abstract

The kinetics of the adsorption of the protein BSA on the ion exchanger Q-Sepharose FF were measured for several values of the pH and ionic strength, using several techniques. The measurements were best described with a model incorporating both surface and pore diffusion and with the chemical potential gradient as the driving force for diffusion. The surface-diffusion coefficients from this model show an inverse exponential dependency on the binding strength. This dependency can be explained by an activated jump mechanism. The pore-diffusion coefficient is much lower than that in free solution, which is probably caused by a combination of steric and electric exclusion.

Ancillary