title: Hydrophobic interaction chromatography of proteins IV. Kinetics of protein spreading.
abstract: Adsorption of proteins on surfaces of hydrophobic interaction chromatography media is at least a two-stage process. Application of pure protein pulses (bovine serum albumin and beta-lactoglobulin) to hydrophobic interaction chromatography media yielded two chromatographic peaks at low salt concentrations. At these salt concentrations, the adsorption process is affected by a second reaction, which can be interpreted as protein spreading or partial unfolding of the protein. The kinetic constants of the spreading reaction were derived from pulse response experiments at different residence times and varying concentrations by applying a modified adsorption model considering conformational changes. The obtained parameters were used to calculate uptake and breakthrough curves for spreading proteins. Although these parameters were determined at low saturation of the column, predictions of overloaded situations could match the experimental runs satisfactorily. Our findings suggest that proteins which are sensitive to conformational changes should be loaded at high salt concentrations in order to accelerate the adsorption reaction and to obtain steeper breakthrough curves.
authors.affiliation: Department of Biotechnology, University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
authors.forename: Emmerich
authors.initials: E
authors.lastname: Haimer
authors.forename: Anne
authors.initials: A
authors.lastname: Tscheliessnig
authors.forename: Rainer
authors.initials: R
authors.lastname: Hahn
authors.forename: Alois
authors.initials: A
authors.lastname: Jungbauer
mesh_terms: D000327:Adsorption; D002845:Chromatography / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008962:Models, Theoretical; D011506:Proteins / Q000032:analysis* / Q000737:chemistry*
chemical_list: D011506:Proteins