Glucose dehydrogenase of bovine heart: activity, purification and properties of the enzyme

The activity of glucose dehydrogenase (EC 1.1.1.47; GDH; glucose NAD(P) oxidoreductase) was demonstrated in the supernatant obtained after centrifugation (1500 g) of bovine heart homogenate. More than 50% of GDH activity was found in the microsomal fraction. The optimum pH for the microsomal enzyme was 8.9. About 200-fold purification of GDH was achieved by successive application of ultracentrifugation in 0.25 M mannitol, treatment with solid ammonium sulphate, and CM-32 cellulose chromatography. The purified preparation oxidized not only glucose but also D-glucosamine, N-acetylglucosamine and xylose in 87, 63 and 23%, respectively. Purified GDH was inhibited by p-chloromercuribenzoate and glucose 6-phosphate.