WOS: 000088071900021Carboxymethylcellulose (CMC) beads were prepared by a liquid curing method in the presence of trivalent ferric ions, and epicholorohydrin was covalently attached to the CMC beads. Polyphenol oxidase (PPO) was then covalently immobilized onto CMC beads. The enzyme loading was 603 mu g g(-1) bead and the retained activity of the immobilized enzyme was found to be 44%. The K-m values were 0.65 and 0.87 mM for the free and the immobilized enzyme, and the V-max values were found to be 1890 and 760 U mg(-1) for the free and the immobilized enzyme, respectively. The optimum pH was 6.5 for the free and 7.0 for the immobilized enzyme. The optimum reaction temperature for the free enzyme was 40 degrees C and for the immobilized enzyme was 45 degrees C. Immobilization onto CMC hydrogel beads made PPO more stable to heat and storage, implying that the covalent immobilization imparted higher conformational stability to the enzyme. (C) 2000 Society of Chemical Industry
