Purification and Characteristics of ${\beta}$-Galactosidase from Strawberry

딸기 ${\beta}$-Galactosidase의 정제 및 생화학적 특성

${\beta}$-Galactosidase was extracted and purified from strawberry. The purified ${\beta}$-Galactosidase from strawberry was investigated their physicochemical characteristics. ${\beta}$-Galactosidase was purified 25.74 fold from strawberry. The purification procedure include ammonium sulfate fraction, acetone powder treatment and gel and ion exchange chromatography. Yield of the enzyme purification was 18.11%. The purified enzyme has native molecular weight of 116,000 dalton. Vmax value and Km value of ${\beta}$-Galactosidase were 0.077 mM ONPG/ml/15mim and 1.75x10-2mM, respectively. The optimum temperature and pH of ${\beta}$-Galactosidase were 43$^{\circ}$C and pH 4.0, respectively. The ${\beta}$-Galactosidase activity was stable below 50$^{\circ}$C and at pH 4.0 to pH 6.0. Among the metal ions Ca and Mg were did not affect, whereas K, Cu and Zn show a little effect on the enzyme activity. The ${\beta}$-Galactosidase activities were inhibited by treatment with EDTA and SDS.