الملخص

ABSTRACT The research was concerned with isolation of alkaline phosphatase (ALP) from the aqueous extract of Aloe Vera using gel filtration technique. It was shown that, using gel filtration chromatography on Sephadex G-100, the solution of the proteinous precipitate produced by ammonium sulphate saturation, contained two proteinous peaks. The two peaks possessed a variable activity of alkaline phosphatase, where maximum specific activity was obtained in the first peak with higher molecular weight which showed (28) folds of purification. Furthermore, the comparative molecular weight of the partially purified alkaline phosphatase (first proteinous peak) using gel filtration was found to be (147353) Dalton. The research was also concerned with finding the optimum conditions of alkaline phosphatase. Maximum activity was obtained using sodium carbonate- bicarbonate buffer (100 mM) at pH ( 9.7 ), (50ºC) and (30 mM) of di-sodium phenyl phosphate as a substrate. Using linweaver-Burk plot, it was found that the Vmax and Km have the values of (185.18 enzyme unit/dl of proteinous solution) and (3.9mM) respectively. The results also predicted that the activity of alkaline phosphatase decreased gradually and reached 76% and 50% from the original value when stored at 4ºC and at room temperature (33-40ºC) respectively for 30 days.