Protective effect of dextrans on glucose oxidase denaturation and inactivation

摘要

In the present study, the stabilizing effect of dextrans as additives on the denaturation and inactivation of glucose oxidase (GOD) was investigated. Three different molecular weighted dextrans (M_W 17.5, 75,188 kD) were used with different concentrations. Dramatically increased enzyme activities were measured after one hour of incubation of enzyme with additives between 25-40degC in water bath. Highest activity value was measured with 75 kDa molecular weighted dextran (in concentration 30% w/v) at pH 5. Dextran as an additive supplied a long shelf-life to the enzyme at 4degC. In the presence of the 75 kDa dextran, the enzyme was more stable and its activity was increased 2.7-fold at 30degC. In addition, dextran protected GOD against inactivation by a n-heptane/aqueous buffer-stirred system.