Purification and enzyme properties of a β-glucosidase from helix snailase

The β-glucosidase which could hydrolyze the ginsenoside-Rb 1 was purified from Helix snailase through a combination of DEAE chromatography and gel filtration chromatography.The β-glucosidase was purified to apparent homogeneity on SDS-PAGE.The optimum pH was 5.6 and the optimum temperature was 80 ℃.The enzyme was stable below 60 ℃ and from pH 4 to 11.The presence of Na +,K +,Li +,Ca 2+,Mg 2+,EDTA,DTT and SDS had no obvious effect on the enzyme activity,while Cu 2+,Ag + and Fe 3+ ions play an inhibitory role.The Km and Vmax values for β-D-glucopyranoside(pNPG)as the substrate were calculated to be 0.182 mmol/L and 0.189 units/mg of protein respectively.