Isolation, purification and determination of some biochemical properties of ß-glucosidase from grape (muscat of Bornova)

This research was undertaken to determine some of the biochemical properties (optimum pH, optimum temperature, heat inactivation, and effect of inhibitors) of ß-glucosidase (ßG, EC 3.2.1.21) which was isolated from Muscat of Bornova grape and partially purified.The optimum pH for ß-glucosidase activity was found to be 5.0 and the enzyme showed high activity over a broad pH range of 4.5-6.0. The optimum temperture for ß-glucosidase activity was 55 °C. Enzyme activity was more than 70% between 45-70°C. According to thermal inactivation studies kD values increased as the temperature increased whereas half-life and D values decreased. Energy of activation (Ea) and Z values were found to be 120.99 kj/mol (r²=0.9776) and 18.08°C (r²=0.9750), respectively. Ca+2, D-glucose and ethyl alcohol inhibited the enzyme at varying degrees depending the concentration.