beta-glucosidase was extracted and purified from Turkish Hacihaliloglu apricot variety and some of its biochemical properties were studied in a two-year study (2008 and 2009). Two isoenzymes (isoenzyme A and B) were obtained upon ammonium sulfate fractionation, ion exchange chromatography using DEAE-Toyopearl 650 M and gel filtration chromatography using Sephadex G-100. The pH optimum was found to be 5.0 for both isoenzymes. The optimum temperature for isoenzyme A activity in both years was found to be 50 degrees C, whereas those for the isoenzyme B in 2008 and 2009 were 50 degrees C and 55 degrees C, respectively. Km values of the isoenzyme A and B were found to be 2.49 and 1.12 mM in 2008, and 2.41 and 1.06 mM in 2009, respectively. The Z values for isoenzyme A in 2008 and 2009 were found to be 20.3 degrees C and 17.9 degrees C, respectively. Those for isoenzyme B in 2008 and 2009 were 21.1 degrees C and 23.0 degrees C, respectively. Ea values for isoenzyme A were 108.1 kjimolK and 1223 kj/molK, while those for isoenzyme B were found to be 103.5 kj/mol K and 95.1 kjimolK in 2008 and 2009, respectively. Of the inhibitors tested, CaCl2 was the most effective. (C) 2017 Elsevier Ltd. All rights reserved.