Microcalorimetric studies of the hydrophobic interaction between proteins and ligand of ion-exchanger resins

• Main Authors: Chiung-I Fang, 方瓊儀
• Other Authors: Wen-Yih Chen
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/61431752632319898603

碩士 === 國立中央大學 === 化學工程與材料工程研究所 === 90 === Abstract The interaction mechanism of proteins with various commercial available cation exchangers at different binding conditions were studied. The aim of this research is the study of the hydrophobic effect of the ion exchanger ligands on protein binding behavior at high ionic strength. In this investigation, proteins, Lysozyme and Myoglobin, were bound to the absorbents which were selected to encompass the hydrophobic effects of three different ion exchanger ligand groups (CM Sepharose, SP Sepharose and SOURCE 30S). Under these experiment were modulated with different types of salt and at high ionic strength. The adsorption behavior were analyzed with batch isotherm and adsorption enthalpies, directly measured by isothermal titration calorimeter. Experimental results indicated that the adsorption mechanism mainly by hydrophobic interaction occurs at high ionic strength and the binding enthalpies confirm this suggestion. In high ionic strength conditions, the enthalpy play a unfavior role in driving the process and the adsorption is driven by entropy gained from the dehydration and desolvation processes. In addition, binding affinities and enthalpies were found to be ligand-dependent, and the most hydrophobic lgands (CM Sepharose) has the highest binding affinitiy among the ligands studied. The presented data shed light on the influence of the hydrophobic effect of the ion exchanger ligands on the protein binding at high ionic strength condition.