Karakterisasi dan penentuan parameter kinetik enzim beta galaktosidase dari Enterobacter cloacae

Abstract

β-galactosidase is an enzyme that can convert lactose into glucose and galactose. Β-galactosidase enzyme produced from various organisms include plants, animals and microorganisms. The purpose of this study was to characterize (activity, optimum pH, optimum temperature, activators, inhibitors and the level of purification) as well as determine the kinetic parameters (Vmax and KM) β- galactosidase enzyme from Enterobacter cloacae. Bacteria were grown in lactose media, peptone, and yeast (LPY) that contain lactose 2%, peptone 1%, 2% yeast extract, and 1% NaCl in 1 liter of distilled water. The optimum condition of β- galactosidase from Enterobacter cloacae was on production time 18 hours, pH 7 and temperature 35 °C. Metal ions (Ca2+, Hg+, Cu2+, Co2+, Zn2+, Mg2+, and Mn2+) is an inhibitor of the enzyme β-galactosidase, whereas Mg2+ and Mn2+ are known role as an enzyme activator. The result of the determination of kinetic parameters of β- galactosidase enzyme which was purified by ammonium sulfate precipitation and dialysis Vmax obtained at 8.850 μmol / min and KM at 0.274 mM, whereas the crude extract obtained Vmax value of 29.412 μmol / min and KM values of 1.118 mM.