Isolation, purification, and investigation of some properties of glucose oxidase of the wood-degrading fungus Lentinus (Panus) tigrinus strain VKM F-3616D

The activity and some properties of glucose oxidase (EC 1.1.3.4) of the wood-degrading fungus Lentinus (Panus) tigrinus VKM F-3616D were studied. The results showed that 12 days of dynamic liquid-phase cultivation increased the activity and the biosynthetic levels of the enzyme with maximal activity at day 6. After 6 days, a decrease in the glucose oxidase activity was observed. The enzyme isolated via ion exchange chromatography had an optimal pH of 4.0 and a temperature optimum of 50 °C. Spectrophotometry, fluorescence analysis, and IR Fourier spectroscopy showed that the enzyme was a flavoprotein and that its prosthetic group contains flavin adenine dinucleotide. The relative kinetic parameters of the enzyme were determined: the Michaelis constant (Km) was 4.1 x 10-3 M, and the maximal rate of the enzymatic reaction (Vmax) was 0.36 IU. Results of electrophoresis in native and denaturing conditions were consistent with an enzyme structure having two equal subunits with a total molecular mass of approximately 160 kDa.