Starch phosphorylase has been isolated from cabbage (Elephantopus scabar) leaves and partially purified using ammonium sulfate fractionation. The partially purified enzyme was desalted using Sephadex-G-25 chromatography. In the direction of polysaccharide synthesis, the enzyme showed optimum activity at pH 6.0 with two half pH optima at pH 5.3 and pH 7.1 whereas in the direction of glucose-1-phosphate formation, it showed optimum pH at pH 7.0 with half pH-optima at pH 6.4 and 7.6. The optimum temperature for the enzyme activity has been found to be 37ºC with two half temperature optima at 34ºC and 40ºC. The partially purified enzyme has been immobilized using egg shell as solid support. The percentage retention of the enzyme on egg shell was nearly 56%. After immobilization, specific activity of the enzyme increased from 0. 0225 to 0.0452. Upon immobilization, there was a slight alkaline shift in the optimum pH when assayed in both the directions. The immobilized enzyme also displayed increased optimum temperature and thermo-stability and could be reused number of times. The increase in thermo-stability and reusability of the immobilized enzyme has been exploited for the production of glucose-1-phosphate, a cytostatic compound used in cardio-therapy. The glucose-1-phosphate produced has been purified with nearly 95% purity after adsorption chromatography on norite and ion exchange chromatography on DEAE cellulose.
Starch phosphorylase; Immobilization; Glucose-1-phosphate; Egg shell; Cabbage
