Abstract
Glucoamylase (α-1, 4 Glucan glucohydrolase, Exo1, 4, α-glucosidase E.C. 3.2.1.3.) from Rhizopus niveus was immobilized to cyanogen bromide-activated dextran. The glucoamylase-dextran conjugate was purified by gel filtration chromatography. It was found that 92% of the original protein of the enzyme was recovered in the conjugate and about 82% of the specific activity of the native enzyme retained. Some properties of the enzyme conjugate were investigated and compared with those of the free enzyme. The pH activity and pH stability of the immobilized enzyme were not much altered with the optimum pH at 5.5 as that of the free enzyme. Immobilized enzyme exhibited a wide range of temperature stability of 50-60°C as compared to the free enzyme. Heat inactivation at 55°C had less effect on the residual activity of the immobilized enzyme in which 60% activity was retained after prolonged heating for 60 minutes.
