title: Lysozyme adsorption onto a cation-exchanger: mechanism of interaction study based on the analysis of retention chromatographic data.
abstract: In this study, based on the analysis of retention chromatographic data, we examined the adsorption of lysozyme onto carboxymethyl cellulose. Lysozyme retention data was collected at pH 5 and pH 8. The sodium chloride (NaCl) concentration in the mobile phase ranged from 300mM to 500mM and the temperature for this study varied from 288K to 308K. The retention measurements generated from these experimental conditions were analyzed with the Van't Hoff method, the preferential interaction model and the stoichiometric displacement model. Endothermic heats-of-adsorption and increases in entropy were observed under certain experimental conditions. These data suggest the presence of entropic driving forces such as the release of water and/or possibly structural changes in lysozyme molecules adsorbed to the surface of carboxymethyl cellulose. The modest observed exergonic adsorption ΔG° and the preferential interaction analysis corroborate the presence of water-release for this study. Additional analysis with the stoichiometric displacement model method revealed negligible changes in the structure of lysozyme molecules in contact with the surface of carboxymethyl cellulose.
authors.affiliation: CICS-UBI - Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal.
authors.forename: F S
authors.initials: FS
authors.lastname: Marques
authors.affiliation: CICS-UBI - Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal.
authors.forename: G L
authors.initials: GL
authors.lastname: Silva
authors.affiliation: Department of Water Resources Management and Environmental Engineering, College of Science and Engineering, Central State University, Wilberforce, OH, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Thrash
authors.affiliation: CICS-UBI - Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal; Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal. Electronic address: ccabral@ubi.pt.
authors.forename: A C
authors.initials: AC
authors.lastname: Dias-Cabral
mesh_terms: D000327:Adsorption; D002411:Cation Exchange Resins / Q000737:chemistry*; D002852:Chromatography, Ion Exchange / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009113:Muramidase / Q000737:chemistry*
chemical_list: D002411:Cation Exchange Resins; D009113:Muramidase
keywords: Carboxymethyl cellulose; Ion-exchange chromatography; Lysozyme; Preferential interaction analysis; Stoichiometric displacement model; Van’t Hoff analysis