ABSTRACT
This chapter reviews the ion-exchange equilibrium behavior of amino acids and the implications on ion exchange of peptides and proteins. It summarizes fundamental features of fixed-bed processes of concentrated systems and dynamic behavior in typical chromatographic processes. Ion-exchange equilibria of biochemicals are much more complex than those of small inorganic ions, and the complex equilibria directly affect their chromatographic behavior. Most large-scale chromatographic processes are directly scaled up from studies of analytical-scale systems. The electrostatic interactions between the oppositely charged groups play an important role in determining its quaternary and tertiary structures. The charges come from the ionization of weak acid or weak carboxyl based groups of its amino acid residues. The chapter focuses on the computer simulated dynamics of typical fixed-bed processes, which include effluent histories and concentration profiles of various components as a function of time. It examines the dynamics of focusing without considering any interference effects.
