PURIFICATION AND CHARACTERIZATION OF BETA-GALACTOSIDASE FROM MUCOR PUSILLUS

The beta-galactosidase from Mucor pusillus was purified by acetone pre cipitation, gel filtration and ion-exchange chromatography. Its molecu lar weight was 129 kDa on SDS PAGE, and its pi was 4.55. Optimum activ ity was observed at pH 4 and at 65C. Thermal denaturation at temperatu res above 60C was essentially first order with an activation energy of 26.4 KJ/mole. Activity was not affected by metal ions or EDTA but was inhibited by galactose and galactono 1-4 lactone. The K-m for lactose at 37C was 22 mM. The enzyme was devoid of cysteine/cystine and stain ed positive far carbohydrate. Overall the enzyme is similar in structu ral and kinetic properties to the beta-galactosidase from Aspergillus niger.