The extended Elution by characteristic Point Method to determine Adsorption Isotherms of Labyrinthopeptin for Purification via Ion-Exchange Chromatography

Ion-exchange chromatography (IEC) is the most frequently used technique to purify proteins and therefore, plays an important role in process development for therapeutical proteins. To improve the purification using ion-exchange chromatography, adequate characterization of adsorption isotherms is obligatory. The Elution by Characteristic Point method (ECP) can be used to determine adsorption isotherms applying only minor amounts of sample material to the chromatography column. Here, the applicability of the extended ECP method to determine adsorption isotherms of the model protein bovine serum albumin (BSA) using bovine hemoglobin (bHb) as tracer substance to quantify all nonidealities of the system is shown. The resulting isotherm was validated using the static batch approach. In the next step, the gained knowledge is used to measure isotherms of Labyrinthopeptins A1 and A2, which show promising activity against retroviruses like herpes simplex virus or human immunodeficiency virus.