Anion exchange chromatography
1. In the purification, the pH of the PBS buffer was6.5, and the two proteins have different isoelectric points(Haemoglobin pI: pI 6.8; Catalase: pI 5.4). What are the chargestates of the two proteins at this pH? (e.g. positively charged,negatively charged or neutral)
2. Based on the charge states of the proteins, whichprotein has a higher affinity to the DEAE-Sepharose resin at pH6.5?
3. Why was the salt concentration of PBS bufferincreased (from 17.5 mM to 175 mM) in order to elute out thecatalase protein?
