Purification and properties of #beta#-glucosidase from Aspergillus aculeatus SM-L22

A #beta#-glucosidase component from Aspergillus aculeatus SM-L22 was separated and purified by exclution chromatography and ion-exchange chromatography. By SDS-PAGE and IEF, the molecular weight of the enzyme was determined as 57.9kD and the isoelectric point was pH4.5. The enzyme showed optitmal activity at pH 5.0 and 60degree C. It was stable in pH 3.0-10.0 and under 40degree C. The result showed that the enzyme can only act low molecular #beta#-glucosidic compounds such as cellobiose, Salicin and lactose. The Km, Vm and Kcatt was 17.13X10~(-3 mol/L, 3.456X10~(-4 mol/L/min and 3.75 S~(-1 when cellobiose was as substrate, and the parameters were 11.93X10~(-3 mol/L, 7.139X10~(-4 mol/L/min and 7.73 S~(-1 respectively, when D-(-)-Salicin as substrate. Fe~(2+, Mn~(2+ can activate the enzymatic activityt and EDTA inhibite it.