Studies on the physical properties of polyethylene‐g‐acrylic acid to immobilizing glucose oxidase

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Abstract
A new type of polymer support for immobilizing glucose oxidase was investigated. The starting copolymer was acrvlic‐acid‐grafted polyethylene (PE‐g‐AA). The copolymer was prepared with gamma ray irradiation induced grafting under controlled conditions utilizing post‐irradiation procedures. A number of factors were examined. They were: (1) the effect of the hydrophilic/hydrophobic nature of the support on the enzyme membrane activity; (2) the Michaelis constant (km); (3) the thermal stability, the rate constant for the thermal denaturation, and the activation energies for the denaturation of immobilized and soluble enzyme; and (4) the physical properties of the support affecting the immobilized enzyme activity. An attempt was made to immobilize the enzymeutilizing carbodiimide (CMC) as the coupling agent. This immobilization method resolves in a high enzyme activity. The hydrophilicity of the support and the activity of the enzyme membrane were proportional to the degree of grafting. When the temperature was higher than 60°C, the immobilized glucose oxidase was less sensitive to thermal inactivation than the native enzyme. Various polyethylene was studied; the LLDPE was preferred. The type of polyethylene, the thickness, kind of grafting monomers, and the degree of grafting would influence the activity of the enzyme membrane.