Abstract
Rapid spectrophotometric assay of mutarotase activity with β-D-glucose dehydrogenase for 3 min was deviced. The reaction system composed of 960μl of 50mM Tris-HCI buffer (pH 7.4), 10μl of β-D-glucose dehydrogenase solution (2,500 units/ml), and 15μl of 200mM NAD+. When 15μpl of 100mM α-D-glucose was added, a slow increase of absorption (A) of NADH at 340nm due to dehydrogenation of β-D-glucose formed from α-D-glucose nonenzymatically was recorded. Mutarotase was then added to record a rapid absorption (B) of NADH due to dehydrogenation of β-D-glucose formed from α-D-glucose nonenzymatically and enzymatically. The difference (B-A) of two rates of NADH formations corresponds to the activity of mutarotase.
