Chloroperoxidase (CPO) was covalently immobilized on poly(hydroxypropyl methacrylate-co-polyethyleneglycole-methacrylate) membranes, which were characterized, by swelling test. FT-IR spectroscopy, scanning electron microscopy, and contact angle measurement. The K(m) and V(max) values for free and immobilized CPO were found to be 34.6 and 47.2 mu M, and 287.5 and 245.2 U/mg protein, respectively. The optimum pH for both the free and immobilized enzyme was observed at 3.0. The immobilized enzyme showed wide pH and temperature profiles. Most importantly, the increased thermal, storage and operational stability of immobilized CPO should depend on the creation of a comfortable strong hydrophilic microenvironment on the designed support to the host enzyme molecule. (C) 2010 Elsevier Ltd. All rights reserved.