Intracellular glucose oxidase from Penicillium funiculosum 46.1

A method for isolating extracellular glucose oxidase from the fungus Penicillium funiculosum 46.1, using ultrafiltration membranes, was developed. Two samples of the enzyme with a specific activity of 914-956 IU were obtained. The enzyme exhibited a high catalytic activity at pH above 6.0. The effective rate constant of glucose oxidase inactivation at pH 2.6 and 16 degrees C was 2.74 x 10(-6) s-1. This constant decreased significantly as pH of the medium increased (4.0-10.0). The temperature optimum for glucose oxidase-catalyzed beta-D-glucose oxidation was in the range 30-65 degrees C. At temperatures below 30 degrees C, the activation energy for beta-D-glucose oxidation was 6.42 kcal/mol; at higher temperatures, this parameter was equal to 0.61 kcal/mol. Kinetic parameters of glucose oxidase-catalyzed delta-D-glucose oxidation depended on the initial concentration of the enzyme in the solution. Glucose oxidase also catalyzed the oxidation of 2-deoxy-D-glucose, maltose, and galactose.