Lysozyme could be efficiently purified using affinity precipitation by using a pH-responsive polymer
PMMDN with L-thyroxin as affinity ligand. A pH-responsive polymer PMMDN was polymerized and subsequently
coupled with L-thyroxin as the ligand. The pI of the affinity polymer was 4.65 and the recovery
was 96.7% of its original amount after recycling three times