Bacterial or insect cell based expressed proteins are prepared using different purification techniques. These are chromatography based techniques based on different characteristics of our target proteins. Tagged variants of proteins are usually the starting point of our purifications pipelines and are subject to affinity based purifications. Usually, the next step is to cut the Tag and thereby releasing the target protein. Next steps are usually Ion-Exchange chromatography including their optimization and finally size exclusion chromatography as a polishing step.