Purification and characterization of beta-D-galactosidase from the pulp of sapota (Achrus sapota) fruit

beta-D-galactosidase (E.C. 3.2. 1.23) from pulp of sapota (Achrus sapota) has been isolated. The enzyme extract was purified by a combination of 80% ammonium sulphate fractionation and combined anion exchange chromatography with DEAE Sephadex A-50 and CM Sephadex C-50. The purified enzyme showed an apparent molecular weight of 120, 200, by gel filtration. The enzyme had an optimum substrate, pH and temperature at 0.5 mM, 5.0 and 50 degrees C, respectively, with p-nitro phenyl - beta-D-galactopyranoside as substrate.