PARTIAL PURIFICATION AND CHARACTERIZATION OF b-GLUCOSIDASE FROM ALOE VERA L. LEAVES

Abstract

The partial purification of β-glucosidase from the pulp of Aloe vera L. Burm. fil. (sarisabir) leaves and some of its kinetic properties is presented. The fresh leaves of A. vera were used; the gel portion was separated and the remaining leaf pulps were cut into small pieces. The crude extract was prepared by homogenization of the leaf pulps in phosphate buffered saline (PBS), pH 7.4 and subsequent centrifugation. β-Glucosidase active fraction was precipitated by 30%-65% ammonium sulphate from the crude extract. Hydroxylapatite column chromatography resulted in a single peak showing β-glucosidase activity eluted with 200 mM phosphate buffer. The partially purified enzyme showed two protein and a single activity band in polyacrylamide gel electrophoresis. It was found that the enzyme exhibited maximum activity at 50 o C and at pH 4.4. Km and Vmax values for 4-nitrophenyl-β-D-glucopyranoside were 6.8x10 - 4 M and 4,58x10 -3 U, respectively. When β-glucosidase activity was investigated throughout the year, it was found that the activity increased in winter and decreased in summer.